> Why? The tech world, like any other business place, is a mixture of people with different attitudes and personalities. If you clearly would have a personality clash with someone, why would it be worth hiring them?

Easy, because they have the knowledge and experience you need for the job. If you're a professional you'll find a way to work with anyone. Yes, you'll have personality clashes from time to time but I have yet to work at a place where that didn't happen.