"What I really hate is... "

What I really hate is When people say to do one thing then go and do another. The reason I hate it is because when some one tells me to do something then go and do something completely different. It makes me feel like my ideas and ways of doing things are wrong. One example is when I was in my science class at prague my teacher told me a way to do a something then went up in front of the class and told every one else a different way then said my way was wrong even though he's the one that told me to do it that way.