An interesting and amusing piece. I confess I have a lot of opinions on books, films, and writing in general, and none of them are particularly humble. ;) Here's a piece I wrote on film adaptations of books, for instance, detailing the good, bad, and ugly. Nor do I pretend to give an airborne fornication about fashion.

But having strong opinions doesn't necessarily mean you have to deride other people in the manner described by you here, with the bloke who ended up with your drink in his face. Such behaviour is arrogant and immature, regardless of age and talent.

Yes, I think it is important for writers to be possessed of a certain belief in themselves. After all, we need to silence self-doubt in the belief that others will want to read what we write. On the other hand, I think it is important to cultivate a self-deprecating sense of humour and laugh at yourself as a writer. It's an important counterbalance that helps writers be more tolerable to their fellow humans.