Random Passwords

For some reason I'm always mixing up my passwords. I know that some people tend to unify them somehow but I totally used the wrong one for blogger! Strange topic, I know but I realize now that I have four or five set passwords that I use. I have the same for certain sites, and different one for others. Maybe I should make them all the same? Is that a stupid idea? Eh. I've come to realize that have diversity when it comes to passwords isn't a good idea due to the fact that you might mix them up or get them all wrong.