When I was a freelancer working on my own, a few companies would include a non compete clause. I challenged them on this always and they were all very happy to alter the wording. It's about the wording mostly, and about definition of competition. For example if I am working for a web agency shop that does e-commerce websites for sports and I am just working on a site for a surf shop, I would alter the clause to read "in the realm of surf shops" rather than competition in general. They were happy to change it because it kept the spirit of the agreement, what they actually meant there. Yeah, I was fine not making directly competing in a specific domain, but I wasn't going to be limited by contract in competing in a general sense. It was also clear that reducing from 12 months to 6 months is usually acceptable also.

Now. The worst clause in a permanent contract is the other works / open source projects etc. They sometimes want to own all your code even the things you do in your spare time. They will ask for a list of all projects you contribute to before working, and if you want to contribute to something new in your spare time you will need approval from management. Now, I think this is very unreasonable, and I've pushed back on this so much that I've rejected job offers because of it. What I do in my own time is my business.