Interestingly, when I am presented with an employment contract, there are two things that often appear and that I always require to be removed: noncompete clauses and wording that assigns the rights to all of the work I do (even work that does not use my employer's time, resources, or knowledge) to my employer.

I have never once had an employer refuse to remove or modify those terms, but a couple of times it took a bit of negotiation to get there.