OK, a huge one for me is "No serious technical questions in the interview." Seriously - if you don't show me code in the interview (preferably code from your products), then I don't really want to work for you. If we don't have at least one good argument about why language X is better than Y, I don't really want to work for you. Or, at the very least, if you don't stress to me at least one difficult technical problem that I'll face, I don't really want to work for you. Why? Because if you don't ask me these things, you've told me that my job is going to be deadly boring, and honestly I'd prefer minimum wage to a boring job.
I'm with you on the "no serious technical questions" thing. It's a really bad sign.
However, it's also a really bad sign when all they seem to do is ask difficult technical questions. About a year ago, I went on an interview where I was asked to:
-create the dual of the primal (linear programming)
-calculate the long term state of a markov chain
-recursively and then iteratively traverse a binary tree
-code a singleton
-write a query that eliminates all dups (sql)
-find a way to rewrite a query as a set of binary indicators (wierd)
-find a way to swap two integers without creating a third integer
... and more stuff that I forget now
at the end of 7 hours of technical grilling, I knew nothing more about what this company's products actually did than I had gleaned from my own web research prior to the interview.
They didn't end up wanting me. But I can't say I really wanted them either. When this happens, I get the feeling that they're looking for, and probably getting, highly talented technical people, but I have doubts as to whether these programmers are actually innovating on the product itself, and that kind of creativity is very important to my enjoyment of a job.
