And WN (Southwest Airlines) has smiling customers. And hey, they can't take away upgrades because there aren't any in the first place.

Seriously, Southwest is run by people who are permitted to use their brains and do so regularly. The only thing that doesn't make sense is the amazing generosity of their FF program: I can spend $290 total on 4 round trips and earn an unrestricted free trip worth $300 (or even more if I have an optimal use for it).

Try Southwest. Adjust your expectations of the flight experience itself downward (but not as much as you'd think). It's a bus, but it's a really pleasant one. Kiosks have eliminated most of the queuing.

After you fly them for a while, you will find yourself adjusting your expectations of a FF program and treatment by the staff substantially upward.