@Grandizer: I see your point with tabs vs spaces, although sometimes you have to follow the company style guide, which may require spaces. What I really hate is someone doesn't care of the guidelines, and when I turn on the "View White Space" (Ctrl+R, Ctrl+W) suddenly I see everything mixed up! If someone sticks to spaces only or tabs only, then nothing bad will happen if you change the tab size (but still don't edit anything). But if you mix up things, that's really bad.
I don't necessarily agree with open bracket on the same line. Readability of the source code is much more important than the extra characters what an open bracket in a new line causes. That sometimes even depends on the language (for e.g. C vs C++ vs C#). In C and C# projects I worked on often used open bracket in new line, which can give a distinctive style with the closing bracket, you see the scope clearly. The other style is more dense, I saw often in dense C++ code.
But once again (here also) the worst thing if the developer doesn't follow the actual style guide (whatever it is), and the code is mixed up. I have SO strong temptation to fix those sections, but at the same time I don't want to touch gunky areas, I don't want my name stuck there in any context in the source control.
NEGLIGENCE (if someone just doesn't care, lazy) towards style guides is one of the worst sins!