I was working one day, looking for something to do, when I started noticing something. Girls always tried to pay in exact change, whereas guys just paid in dollar amounts. Guys usually paid with a $20, even though their purchase was only $3. Questions started running through my head about why girls would pay in exact change and guys wouldn't. I came to this conclusion, which I will give proof for in a second. Girls are more detail-oriented about everything than guys are. Girls always have to stop when they see a mirror to see if their hair is still done right or if their makeup has smudged off yet. Most of the careers that require detail-oriented people are filled with females. Guys are only detail-oriented about things they are interested in, like computers, mechanics, or sports. This is the reason that girls pay in exact change, if they have exact change, and guys don't.