Not for a lack of trying, I assure you. It's just that no matter how hard I try, my mind won't accept it.
The thought of life and existence being ultimately meaningless (Something else my mind fights against, despite knowing it's true) is too much of a blow to my psyche to overcome and look at light-heartedly.
I'm just so desperate to have a purpose and meaning in my life, but at the same time I can't sincerely believe in any religion or afterlife. I try to "live in the moment" and "be happy and make others happy", but it just isn't enough. I need something more.
Edit: Thank you everyone for their responses so far, I do read them all. They give me something to ponder and think about, maybe even leading to a solution.
Its easy to look at your achievements and see that they are pointless and meaningless and see some sarcastic humor in that. Laughing at suffering is the hard part. So start with something small. Think of a time when you didn't factor in a simple detail and it made everything go horribly wrong. Now imagine that you are someone else watching you make this obvious mistake and how funny it is.