Evaluating the positions

I've been analyzing some of my games recently and got quite surprised seeing that in some of them i am completely winning, while even not realizing it. "Completely" here meaning that engine says +3.00+ or something like that - and that its not the tactic that I simply missed.

Then I asked myself, after these positions repeated themselves a few times, what I am doing so wrong - why do I keep misevaluating some of these positions?

While researching this I finally realized that the evaluation of the position - naturally (duh) - depends on the depth of the lines I could see and my ability to evaluate it as equal/slightly winning/winning/crushin for example. Now it may me obvious when said this way, but how many times did you evaluate the position by saying "this looks good" - or - "this seems bad" and went on to choose another move? I've done this plenty.

Another important point - When asked who is better in certain position, how do you respond? White seems better/worse.. which is weak vague explanation. Or white is better because of: 1. Move move 2. Move Move 3. Move and wins this/that with promising attack. Thinking in lines is KEY and evaluating each position that is calculated - giving it value that can be used to be compared with alternative moves. Almost everything else is kind of "hope chess".

I described this and maybe a bit more with practical example in the video as well: