Yea, I'm serious. I didn't say that freight pilots were "loners" in a clinical sense, only that they tend to be people who don't need constant interaction with a lot of other people to be happy at their jobs. I'm surprised that you weren't asked about your feelings about working "away from the public eye" at your UPS interview...I know I was.
Flying pax involves a fair amount of contact with the public. Flying boxes involves a fair amount of contact with...boxes. I've done both, and prefer boxes, but I have friends who feel just the opposite. One isn't "better" than the other, just a little different, that's all.
What UPS the company makes each year doesn't necessarily translate into what UPS pilots make. There's no question that it's a very solid company, but so is SWA.
As I see it, especially in the first 6 years, the SWA pilot will work a little harder, fly more legs, and have more interaction with what's behind the cockpit door than the UPS pilot. In exchange for that, he'll do a lot more of his flying on the "front side of the clock" and probably make a little more money in the process.
It's really about preference, that's all.