My impression has been that developers way too often rely on the subsequent use of the debugger when writing code. It’s like, “I don’t really know what I’m doing, but the debugger will help me understand my code... Oh, what a piece of crap I wrote! Let me start over...” Looks almost like people are debugging themselves.
They're much more useful in maintenance environments where people have already written a million lines of code before you got there. Of course you have no idea what they've done. After a few years they probably have no idea either. You can go grepping in the codebase, but the sheer speed of asking the debugger "how did I get here?" is hard to beat.
They're also useful in layered environments. Sometimes it's a bug in other people's code and you need to get in there to find out what's happening. When all you have is disassembly, and can't readily insert print statements, the debugger is absolutely invaluable. One of my own "debugger greatest hits" was finding a bug in Windows CE stack unwinding this way.
