no it's peoples way of coping with things, yours seems to be pretty good if you can stay happy, it is good just to let it out once in a while though. Did you have an experience ealier in life which made you cry a lot and since then you've become emotionally stronger? and now find it hard to cry whenever you want to.

That's a strange way of coping with things i gotta dmit, never heard of laughing when wanting to cry before!