My first (and last) non-compete was when I was starting out as a web developer in a small company. By the time I fully realized what I had signed I had contractually given up my right to work for any other webdev company for 1.5 years, and even worse, the company owner stated that he believed the non-compete also extended to all our clients (and the clients of a major client) too. This meant nearly all banks, Heineken, Google, and consultancy agencies (we ran a job board).

Needless to say I am not a web developer anymore.