Remember my first time? Heck yeah. It was just last month.
By way of background, I've been flying 200-250,000 miles a year for twenty-something years. The miles get spread around among airlines - lots of African national carriers, for instance. So I'm perpetually UA/*A Premier Exec/Gold, but only twice 1K.
I'd never been anywhere but Economy (-Plus) until last month, flying LHR-SFO, I got upgraded to Business. Turned out to be a mixed blessing. No "menu" options for strict vegetarians, and no one was willing to look very hard for my special request meal (destined for Economy) or conjure up an alternative. So I was a hungry traveler when I got to SFO.
In the end I shouldn't have taken the upgrade. I didn't care about the extra space, and (obviously, I s'pose) don't drink beer or wine or whatever. And I don't watch TV/movies or play games. And in Economy, my window seat lets me lean/sleep against the fuselage.