I like this thread.
Shows that I'm not the one who wishes he knew better and did better planning.
But after all, who cares?
I mean, if we made mistakes back then, mistakes which we wouldn't do today, it's because we didn't have the relevant info we have now.
Didn't have the info? It's not your fault.
Don't blame it on yourself, blame it on school/parents/boss/whatever if you have to.