There are several exceptions:
1) you are the CEO or a top exec in a VERY large company. In that case your personal lawyers are involved in the negotiation of the contract, and it is assumed that you know what you are doing. But even in those rare cases, the law in on your side. 2) a non-compete COULD be part of the sale of your company (I wrote YOUR company, you own it, and your are not merely an employee, even senior employee).
Don't confuse that with the IP rights you give up to the company (legales like like we own EVERYTHING you have created or will create). You can still quit tomorrow with no notice given and work for whomever you feel like. Don’t use that IP, and don’t take ANYTHING with you (no files, no customers lists, no lines of code, no presentations, no emails). Then you are fine.