Why big boys don't cry, and why they should!
Nearly every television show, movie, and nearby park that has playing kids will have an adult telling a kid "big boys don't cry". In the United States, it is gender normative for men to appear as strong, tough, and emotionally shallow. These ideals are just as harmful to little boys as little girls.
Teaching boys not to cry is teaching them to bottle up feelings. Feelings are vital to the human existence. If we based all our actions on logic and reason alone, we wouldn't succeed very well as a species. I remember reading about a man in my psychology text book years ago who experienced significant brain trauma and as a result was left with an inability to feel emotions. As a result, he made some seriously flawed life choices based on logic alone - including 4 marriages and divorces.
Gender stereotypes aside, me really do cry! Actors have even won academy awards for crying in films. Tom Hanks received multiple nominations for films in which he cried. As recently as 2010, Colin Firth won for The King's Speech, a movie in which his character cried, and I'm not talking a single "manly" tear either. I have seen every male in my family cry at some point. When my first boyfriend got hit in the face with a baseball bat he certainly cried - and I didn't think any less of him for it!
Our species cries for a reason, and bottling up emotions isn't good. Yes it probably isn't socially ideal for everyone to go around crying at the drop of a hat, but if the situation and your emotions warrant it, don't be ashamed to cry!