In your case, I believe you. That's not the common case, though. Most people who say they know how to discipline themselves just don't; and then other developers suffer for their failings. Self-discipline is hard.

It's like the way 90% of drivers consider themselves "above average" -- they can't all be right, and only a few of them are really as good as they claim.

A good programmer can work within a language to get whatever he needs done, one way or another. It's a question of limiting the amount of damage a bad developer can do (deliberately or by accident) that's hard.