I think this is a cultural thing. There are few traditional English dishes that are supposed to be eaten with fingers...in fact, I can only think of sandwiches!
Italian thin based pizza, which is what we get here, like Chicago pizza is tricky to eat with fingers, so while it is okay to do so at home I would always eat at Pizza Express or other nice places with a knife and fork. Pizza Hut is a bit crap, and the bases are thicker, so that is okay to use hands. Unless out with my mother

I ate hamburgers with a knife and fork until I was about 16. That is because we would would go to Wimpy, who supplied them, rather than MaccyD's, who don't.
If I have chips at home, I'll use a fork, if we are walking then I would use my fingers or a wooden fork.
As for curry...that is meant to be scooped up with bread, no question. But I lived in India so I converted to this method, most Brits would find it wierd.
Vicky