In most cases I’m happy to see a flower appear, but when it comes to basil I get busy pinching whenever I see the beginnings of a bud.
The great purpose, from the plant’s perspective, is to flower and set seed. Once that’s accomplished, it dies. My purpose for the basil plants is lots and lots of pesto. I want to extend the life of my plants as long as possible in order to harvest as many leaves as possible. Nipping their flowers sends the message that things didn’t work out, so they’ll keep growing and try again.