Complaining.

Both of my parents worked but it was my mothers "job" to cook all the meals.  No matter what my mother made my father would complain about it.  Even his compliments were complaints and that's why she stopped caring about the cooking.

She would get home from work and cook/burn/whatever was on sale at the store.  That taught me two things:  food quality was much better when my father was out of town and hunger makes things taste better.  I told my children that I don't like them saying they don't like something before they try it (and once even before I decided what I was going to make).  If they kept it up I would stop trying and just make the stuff I like and if it was burned... then tough, you'll eat when you get hungry enough.

The complaints have slowed down, they are learning.