There is a saying to advise people against working in the same field as your interest, because you will end up hating it. Do you agree?

No and yes. Something like video games... well, on one hand you need a passion for the medium, but on the other, you have to see behind the scenes and how it works, rather than simply enjoying the product. I like to think of my Dad, who studied music. He can't listen to music now and simply enjoy it, he mentally deconstructs every song. It becomes an intellectual exercise, rather than a fun one.

On the other hand, if you're interested in, say, science, then hell yes. You absolutely need a passion for it to break up the tedium

If you work in a field which doesn't interest you, I can't see you being very happy in your job.