The irony is that airlines specifically make economy travel worse so the upgrade seems more justified (there's only so much they can do, waiting for a long time to be crammed in a tin can for an even longer time is never going to be fun). It also thrives on status, people want to be seen to travelling business or first (or those ludicrous designations – super diplomat envoy class and the like, not you're not).
Other than flights to Australasia, the far-east China and LATAM, the mothership insists on economy for this minion. The price difference for business is often 3 or 4x the economy fare, which is a lot for a small bed, silverware, and cabin crew that have have to learn your name (it's only time I get called doctor, and I never want to be a doctor on a plane). I don't mind, of course, as the mothership is paying. I'm stingy when I pay for myself (my wife is a bit more grouchy as she's tall – she's joining me in SE Asia later this year, I'm in business, she's premium economy, and I'm never going to hear the end of that).
That said, I won't say no if someone else is picking up the tab. The lounges are usually far nicer than being in general population.
(The one thing that does annoy me is fast-track security for business/first, I can let the rest go, but I'm pretty sure my taxes pay for border patrol, as do everyone else's.)