My dcs teachers educate them for 30 hours per week for 47 weeks of the year. They are fantastic people who spend a lot of their own time on prepararation and related school work. My kids love school and are doing great and that is down to the teachers. I always write them a card each with heartfelt thanks specifics to each teacher. I give them a gift or club in with other parents for vouchers.
It's so ungracious to say ' why bother giving something to teachers'. It doesn't have to cost anything for 'hard pressed parents' to give a home made card. The comparison with doctors and dentists isn't relevant unless your child spends 30 hours a week at either of these. If my child did I am sure I would be giving that doctor or dentist a card and my sincere thanks! As parents of children in hospital for a long time tend to do.
Why are people so mean spirited to people who do so much for them? Why is saying thank you or showing appreciation considered a negative. Harriet sounds like such a grump I guess not much fun ahead for her kids in the hols.