Embracing change is your friend
Yes. I know. I've invented the most trite post title in the history. But here:
You look back on your life and cringe at that thing you did at 20. Shudder, right? And your 30yo self thought "what a dumbass".
Then your 40yo self comes along and mocks 30yo you for all your huburis.
Do you see the pattern? All of your past selfs are dummies with respect to their slightly-later-selves. The thing that ties all of these past selves together is arrogance.
If your 50yo self looks back on all those kid with mild pity, and optimism about the future because fuck that kid.
After all (again, trite) there's nothing you can do for said kid. Does he exist? At all? If you stop and really think about it, it's a deeply philosophical question which is interesting but its answer is not really all that relevant, is it? 1) time travel exists 2) I can send thoughts and prayers through time 3) ...
What is your great plan about your past you? Do you have great plans for him?
So, should you "actively hate" your past self, since it doesn't matter one way or the other? Well, it will not affect your past self one way or the other, what would "active hate" do to/for your future self?
All obvious/All profoundish.