I can't fake laugh. Well, not a convincing fake laugh.

If you're talking to me and say something funny I'll either not respond or start laughing hysterically

And if I don't laugh (which happens rarely) please don't think too much of it. I'm either having a bad day or am just spacing out.

And if I am having a bad day, it's honestly not that hard to get me to smile. Just speak in a weird voice and make a weird face and I'll go back to being happy again.