“You're big now. Big girls/boys don't cry.”
This one is especially crippling. As a kid, all you want to do is fill the shoes set for you, and even if they are awkwardly shaped or hurt your feet when you put them on, you will do your best to suck it up and deal with it, thinking ‘hey, if other kids can do it then so can I'.
Problem is, other kids most probably feel the same way. Then who, you might ask, has set up this example for kids? Simple. Parents who will do anything to stop their children from disturbing their calmness, even if it means restricting their emotions and risking irreversible psychological damage.
So please, please, if you have a child, take a moment every day to discuss their feelings and I daresay let them cry if they feel like doing so. That way, you'll teach them a valuable lesson, and that is crying doesn't show weakness, but shows that you've been strong for too long.