the nail that sticks up gets hammered down

The nail that sticks up gets hammered down id another way to say that someone or something that sticks out in an obvious way is usually the one who will get an example made out of them. Someone who is very noticeable or stands out in some way, whether physically or literally, they are often noticed by everyone including someone who will be punishing a group of people. This person tends to be the one to be hammered down.