Here are jobs I've done that make me a little more wary in service situations:
McDonald's Manager (worked my way up from grunt, so I've done it ALL)
Radio Shack Salesperson
AT&T Small Business Salesperson
Catalog Phone Order Rep
The truth is that I'm pretty jaded on humanity as a whole based on some of the shoddy experiences I've had. I think also that it makes me more apt to be critical whenever I am the customer.
Anyway, just wanted to *wave* and say hello. Have a good one!