I'm not sure where to direct you.. I have never really had this issue except maybe in the sense that when I've been depressed in the past, I find it hard to be nice and social to people who are ignorant to the suffering of others.

Maybe volunteer somewhere or do something nice for someone; getting out of yourself and seeing someone benefit directly from your actions might help shake you out of the seriousness and sarcastic tendencies.

That's all I got.

Anyway, I thought I would drop by and say something because I noticed you, like me, hadn't gotten any replies yet and seem to have some serious issues relating to other people in a positive way.

I hope you work through whatever you're experiencing, feel free to message me if you need someone to listen.