I've learnt that some people requires more time and effort to grow up and mature. We should all understand and walk away/leave them alone when they do dumb stuff and think that it's really funny. I've also learnt that people have different sense of humor so we should not get pissed off easily, thinking that what they're doing is stupid. Instead we should just hold our heads up high and laugh with them (not at them) because they'll feel hurt if we don't.
If we feel nice, we call these people cute people who are a little weird.
But if we're not, these people are just pathetic, wasting their time doing meaningless stuff and actually enjoying all the crap.
And we should not care about what others say/think of us. We live our lives the way we want, we're not doing all these for others. People who matter wouldn't mind, really. Being happy is really important and it's that kind of happy which cannot be achieved by living the way others want you to. As long as you're happy, nothing really matters. Well, I mean, you only live once right.
Yep, that's all I've learnt :)