I have worked in a school as a TA for over 10 years and have noticed more and more parents coming in to complain. I mean, they complain about the most ridiculous things and think they have the right to tell the professionals how to do their job. But rarely do I see parents pop in to say thank you; thank you for giving up a week taking your child on a residential, thanks for giving up lunchtimes and after school to coach the school football team, thanks for giving up a Saturday to paint the backdrop for the school production etc).
Please remember this next time your child's teacher goes above and beyond... Because, trust me, they do it a lot and never feel appreciated!