I guy I work with says "Humans are lazy...that's why you see people pulling on 'push' doors and pushing on 'pull' doors. We see the same first two letters on the alphabet and we make a guess and 50% of the time, we're right. But why not make it easy on everyone; change the terms on the doors from 'push' and 'pull' to 'shove' and 'yank' - think abou it...much easier."