I'm not sure I've ever known and am not certain I will. I can be happy in a moment, but that goes away. Meds help me shrug it off, and I don't tend to dwell on existential shit like this for long, but like...I dunno that I was cut out for this world, yo.
Also this isn't a cry for help and im not particularly sad or upset right now, I was just walking one of the pups and thought to myself "if I can't be happy I'm gonna make sure these fuckers are."
I was happy for about a year before I fucked everything up with a girl I wanted to marry. Now I find fleeting feelings of happiness when I get to perform on a stage or teach people about cool history shit.