Hate my bike? Never. Hate the conditions (road or weather)? Definitely!
I always feel better after a ride -- sometimes for days. I don't think of it as endorphins kicking in - I attribute it to the good aerobic exercise burning all of the nasty toxins from my body. Back when I was a young foolish lad in college and drank too much, I'd get up at first light, assemble the bike and go out for a 40-60 mile ride. I'd come back two- to three hours later as my roommates were just waking up nursing their hangovers, and I was bright-eyed and bushy-tailed!