One of my guiding principles for code comments has always been "say why not what". If I can't figure out that what on my own then something is probably very wro

One of my guiding principles for code comments has always been "say why not what". If I can't figure out that what on my own then something is probably very wrong with the code. What I want to know is why you used a for() instead of a while() to iterate over an array or things like that. Comments that explain what you're doing I find to be cruft. I don't necessarily hate on them but I do find them unnecessary and unhelpful.