The only times in my life where I've felt twinges of regret fall over me was when I listened to the wrong voice speaking inside my head when decisions were being made by me.
We have two voices playing in our head at all times which offer unsolicited advice to us. Unsolicited to mean, we don't typically ask our inner voices for advice, but instead, that unsolicited advice will be offered to us from both sides of our head whether we want it or not.
One voice is very soft, very quiet and very unobtrusive to our lives, whereas the other voice always speaks first, it always speaks the loudest and it insists that it has the answer to all things we could ever ask about and therefore presents itself as 'all knowing'.
Sometimes that loud voice sounds very convincing, more convincing than the quiet voice, but like a used car salesman ..or like Donald Trump for that matter, the loud voice can absolutely convince us that we can't go wrong if we listen to it's logic and take it's experienced advice at face value and run with it.
The way that I've discovered the difference is when I make a decision to do something which I don't feel totally comfortable about and when it doesn't work out, I always say "damn, I KNEW this would happen!".
The truth is, I DID know that the opposite, less desirable outcome would happen... because that quiet, inner voice was trying to tell me before I made that decision, not to go down that dubious path because doing so would lead to regret, which it always did ...and then I kicked my own asss after the fact for not listening to what I should have otherwise listened to from that quiet voice.
Instead, I listened to that loud voice, the proverbial 'big mouth in the room' that convinced me that IT was 'right', that IT was 'all knowing' and that nothing could go wrong.. go wrong.. go wrong... until it finally did!