Generalizations, or oversimplifications, in your writing can work against you and the proving of your argument because:

Not every woman is looking for a good man.
Not every person believes in god.
Not every man wants to play sports.
Not every human thinks the ideal body image is thin and tan.
Not every American is pro-war.
Not every American is a Democrat or a Republican.
Not every ethnic person can be identified based on his or her skin tone.
Not every aged person is grouchy, weak, uniformed, or afraid.
Not every man thinks hitting a woman is ok.
Not every person thinks racist jokes are funny.
Not every woman wants to be submissive to men.
Not every little girl wants to grow up to get married and have children.
Not every little boy wants to grow up to be a fireman, policeman, or soldier.
Not every ethnic person “lives up” to incorrect stereotypes often placed upon him or her.
Not every person believes nature is a good thing.
Not every person respects the rights of others.
Not every person thinks being good is better than being right.
Not every person believes in sticking up for others.
Not every person thinks violence is a bad thing.
Not every person cherishes children as humans.
Not every person values education over money.
Not every person values money over education.
Not every person thinks he needs love.
Not every woman likes to be treated like a child or a pet.
Not every man thinks he needs to be aggressive to be a man.
Not every person thinks the way you do.

Be careful not to generalize about gender, race, religion, politics, personal decisions, sexual orientation, hobbies, beliefs, and/or any other area for which you might make incorrect or false assumptions.