php mail()

Why is it that Gmail gets mail from mail() fine, but it never goes through to other mail services like hotmail and yahoo?

I've tried using just "From:"; I tried using some other headers (the mime type and character encoding), but that didn't work; I looked in the php manual and added just about every extra header I could find, tried it, and it still didn't work.

Because PHP is a language with C syntax, written in C, but not self hosting and not as powerful as C with OO extentions not even close to C++'s OO extentions for C, with libraries written in C that can't even follow 1 single standard naming convention.

It really is a "language" for shit eating morons. So if you take issue with something it does, remeber it is complete shit written by morons for morons.