"How long have you been gone?"
"I don't know. A year, give or take? Who keeps track?"
"Which countries did you visit while you were away? Your landing card just says 'most of them'"
"Well probably not most of them really, but definitely enough not to fit in that space. Let's see... [followed by a complete list]
"What's your occupation?"
"I own a software company. It pretty much runs itself these days, and I just check in every once in a while to see how things are going."
"Is this bag your only luggage?"
"Yeah. I was only gone a year, remember. I find you don't really need much stuff in the tropics. I've worn this shirt 40 days running now. I think I'll buy a new one now that I'm home"
Basically, it's your opportunity to remind them that their job is to sit in a little cube talking to people who are actually out there leading exciting lives. And that their attempts to make other people's lives worse is not really doing a very good job of making their own life any better.
One day they'll quit and go find a better job. Or give up trying to make other people's lives worse, thus making the world a slightly better place.
Seems to be working. These days at LAX, it seems that one in four of the people manning those desks is genuinely friendly. And the ones that need this sort of treatment are few and far between.