For me, it's about what I lack. I'm an upper person, 100%. I like downers, I even like mixing uppers and downers more, but at my core I love my stims. But stimulants "fix" so many of my "problems." Like, I'm chronically tired and low energy, low motivation, anhedonic, awkward in social situations, usually cannot think of things to talk about even. Not that I don't want to, there's just nothing there no matter how hard I try. They help me focus, they allow me to have fun, etc.
I'm naturally low, so the upper appeals to me because it balances me out and in high doses can even push me over into the other side. And experiencing something like that when you're so typically low is a form of high in itself imo.
Like I said, I like downers, they're fun, but they don't do that for me. They aren't the missing piece. I could take them or leave them no problem.