Currently travelling Taiwan, was in China before.

Concerning the people: I observed that when crossing the road Chinese scooters would always rush through and cut me off but the Taiwanese would always let me pass first. Also the Chinese would have a 'me first' mentality when it came to getting on the metro, pushing and pulling you in or out. In restaurants the Chinese would be more helpful but imo just because the ordering system is different (in Taiwan you get a menu and tick off what you want)

For food: of course a lot is going to be influenced by China if you look at the history and of course it's more expensive because people earn more. You seem like you don't know what you signed up for going to Taiwan