I've read that the rush you get from "the pump" is a function of steroid use
I haven't done a ton of weight training, but I've never felt this euphoria. I've definitely felt the runner's high - but only once after a very very intense run
I'm going to put this one down to interpersonal variation because I'm at best an intermediate lifter (BW 90kg, BP62.5 3x5, SQ85, DL 110 3x5) and I feel awesome after lifting weights. Same thing after doing Ashtanga Yoga. I just feel euphoric after really using my body, like, yeah, I just did that.
The variety of human experience is massive, some people are tetrachromats, some can't visualise at all, some can't experience romantic love.