The term "could have" should be removed from the English language. There's nothing that could've been done differently. NOTHING. We couldn't've (could have not) made different choices than we did, and things couldn't've been different because in the past we didn't have the insight we have right now. This is an an undeniable truth. Past is past (or rather was past) and you can only accept it or suffer. Of course, you could say "I'd rather suffer than accept that X happened". And my reply would be "Then be insane if that's your will. You have every right to be insane. But do you want to?"

Regretting things is insane. The past doesn't exist, so regrets are useless and also harmful because they cause suffering. All you can do is surrender to the fact that you can't change anything that happened (but your ego will try to stop you from doing that).

There's nothing to regret. There's nothing there. It doesn't exist anymore. The only thing that exists is the present moment. The moment you regret something, notice the feeling and realize that what you feel only exists in the form of thought your mind is creating.

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Justice is never fair. To not be an insane egoist is to be forgiving towards yourself and others, and that's the harsh truth. Punishing yourself harms you and those close to you. Punishing others only causes more suffering without being able to fix what had already happened. Don't take the role of karma, as it happens on its own. All you can do is try to prevent bad situations from happening again, and make the culprit compensate their wrongdoings for the victim, but not for the victim's ego. Ego is deadly.

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Don't have anxiety either, as that comes from attachments and the lack of understanding of impermanence. Everything in this 3D world is impermanent. Don't get attached to things that aren't permanent, including opportunities, belongings, relationships and even life. You can lose them at any moment. Relationships can end at any moment but you can be loyal without attachment. People can die at any moment but you can spend all your time with them without attachment. Sadness is temporary, and so is happiness. And in the end, all you need to do to end anxiety is practicing mindfulness and realizing that whatever makes you anxious, doesn't exist. Your mind creates pointless anxiety, and you can stop it from doing that.

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Are you letting your mind make you feel depressed? Or in other words, do you identify with your depression? Because that's the real problem. Depression is never caused by the external world, only by your mind. By your thoughts. It's compulsive negative thinking. The mind creates it when it falls into the downward spiral of fear of some kind. The solution is simple: mindfulness. Neither living in the past nor living in the future. Living where you are right now. Thinking only when it's necessary. Not identifying with your thoughts because believe me, you're not your mind, you're much more than that.

Walking in a forest, grounding yourself, practising inner body meditation, being mindful of every moment, being grateful & forgiving, meditating, doing yoga, paying attention to the present moment, that which you see around you, to your breath, to your inner body. Notice that all these exercises make you focus on the Now. To attain inner peace, independent from happiness and sadness, you start by ceasing to think compulsively, as thoughts take you away from the Now, while all forms of conscious presence bring you closer. You cease thinking by noticing that you're thinking. It's the Quantum Zeno effect.

Don't live in the past or in the future, as the illusion of time leads to suffering. Only the present moment exists; everything else exists in the mind. The past doesn't exist anymore, while the future doesn't exist yet. Don't believe me? Well, if you didn't think about the past, where would it be? Or, can you show me the future? If not, where is it? It's not anywhere. What is, is. What was/will be, is not.

Time only exists in the minds of sentient beings and thinking about it takes us away from reality, which causes suffering. This is why not thinking brings us closer to inner peace. Learning not to think takes effort but it's attainable by anyone who practices, as it rewires your brain. The only reason not to attain this ability is aversion, and nothing external.

Can you be unhappy when not thinking?

Can you?

Sadness is a form of thinking. Mindfulness is the most basic solution to sadness; realising that sadness is there in your mind, yet you transcend it, breathing, living.

Wishing to change the past and fearing the future is insane, as it only leads to unhappiness. Everything happened, happens or will happen in the Now, in the present moment. Isn't it so? But the ego is afraid of losing its identity derived from the past and hopes that it'll get better in the future, which is why it's so difficult to be present. But you don't need to remember your past to be yourself, and you can't have anything in the future, only in the Now. You can't even be happy (or sad) in the future.

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Happiness isn't having what you want. It's being grateful for what you have. The more you resent, so the more you wish for the past to have been different, the more you suffer because changing the past is impossible. The more you desire, so the more you wish for feeling better in the future, the less happy you are in the present. Whenever you have desires, you don't have happiness. Whenever you become timeless, you feel inner peace.

That doesn't mean you can always be happy but even if you're sad, you don't have to suffer. You can still have peace in the present moment even in times of unhappiness. Psychological pain (suffering) and fear are as illusionary as time is. If you feel them, you're not present; your ego has taken over and wants things to be different, whether in the past or in the future. This is the primary sign you're not in control of your "self".

Psychological suffering is always some kind of resistance to the present moment created by the ego/mind. It's always just that; not wanting to accept what is, and wishing things were/will be different, both of which are beyond anyone's control. Not suffering is as simple as realising you can't resist the present moment / the Now / life / what is. You can only yield to it. It's done through practice and the final goal is what they call enlightenment – being immune to suffering, having inner peace no matter what is happening. And it's very much attainable, but not by working hard, quite the opposite – by not doing anything, not thinking, not being stressed, not having desires, not having regrets. By being aware of your mind's activities without judgement. By observing what your mind creates and how it reacts, and labelling it if necessary (is it a vision? a sound? a voice? an emotion? what is your mind doing?). Once you notice what your mind is doing, you also notice you're beyond your mind.

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"If there were nothing but thought in you, you wouldn't even know you are thinking. You would be like a dreamer who doesn't know he is dreaming. You would be as identified with every thought as the dreamer is with every image in the dream."
- Eckhart Tolle - The Power of Now

Have you ever had a dream when you realised you were dreaming but didn't wake up? That's an example of becoming present. Enlightenment is being as present in the real world as it is to always have lucid dreams in the dream world.

That considered, are YOU your mind or are you something more? Do you cease to exist when you have no thoughts, feelings or emotions? Do "you think, therefore you are"? Of course not because you can observe your mind's activities passively and eventually pause them. And you still are. I don't think, therefore I am (present). Everyone who's willing, can do it. A conscious mind is something your ego (the unconscious mind) cannot gras