My completely un-educated guess, which is based on no experience whatsoever haha, is that you probably get the two extremes when it comes to feedback.
People are very excited to vacation, and probably feel a close bond to their TA when it goes well - and that leads to plenty of heart felt "thank you's". On the other hand, when something goes wrong with a vacation, I can see people getting very annoyed, very quickly. I'd be surprised if most TA didn't have at least one story about a customer going absolutely nuts on them.
Just a thought from the peanut gallery.
RCCL - Adventure OTS (Honeymoon!)
CCL - Carnival Miracle
RCCL - Enchantment OTS