Had many a good flight to Panama, and yes we tipped. Hector always had the fuel truck and catering waiting, and always had the flightplan wrong.
Mexico is pretty bad with the 'tipping'.
I would just hate for it to be like that in the US - if I dont tip enough I dont get what I need. When I'm flying around in a lear, we just can't compete with the bigger jets. If we were to match them with some of the tips, as a proportion of our final bill it would be huge. Never went back to First in TEB after they refused to give us a GPU - 'a real plane might need it' he said after pocketing the $10. Was it not enough?