Comments

Why is it that C-coders don't know how to comment code. Almost every piece of source code written in C/C++ is been utterly without comments. MAYBE they'll put a line or two at the head of a function, but after that, it's completely devoid of comments.
Compare this to Perl coders who will deliver an app of 200 lines, where 150 will be very explicit comments.
I know that when you've had your head in a certain piece of code for a long time that you know if inside and out, but when you open source code, you need to make some kind of effort to help others understand what you do. This might not sit well with the elitist jackass crowd, but to you I say this; fuck off!

I can understand what something does without comments, but it helps me to get quirks and odd design choices if there are comments explaining what happens.

Reading Linux kernel sources to figure out how to manipulate a device at the lowest lever might sound like a fun thing to do, but it's not that exciting when there are no comments.