Why Doesn't God Save Everyone?

The Bible says that God desires all men (Men being used generally to mean everyone as the Bible often does.) to be saved, so why doesn't he save all men? If God saved all men, then the Bible would have no need for the warnings, and there would be no Hell, so all men obviously won't be saved. The answer then, is that God wants all men to be saved, but all men don't want to be saved. it'd hard for Christians to understand this, but the simple fact is that some people do not wish to be saved.