it's called the "principle of least surprise." I believe people want to express themselves when they program. They don't want to fight with the language. Programming languages must feel natural to programmers. I tried to make people enjoy programming and concentrate on the fun and creative part of programming when they use Ruby.
Yukihiro Matsumoto, creator of Ruby and the human factor:
Imagine you are writing an email. You are in front of the computer. You are operating the computer, clicking a mouse and typing on a keyboard, but the message will be sent to a human over the internet. So you are working before the computer, but with a human behind the computer. Most of the tasks we do are for humans. For example, a tax calculation is counting numbers so the government can pull money out from my wallet, but government consists of humans. Most of our tasks are related to humans after all.
~ Yukihiro Matsumoto, creator of Ruby