I hate to bring it back to pizza (no, I don't, actually) - I was once told that traditional pizzerias didn't serve other food like pastas (which require cutlery) because - traditionally - pizza is meant to be eaten with your hands (sans cutlery). The influx of tourism has changed the face of this tradition, according to this man who ran his restaurant in Florence.
Just do it, mate. It's not an evening thing, that's for sure. Wore white chinos (+ denim shirt + navy sweater) last Saturday at a mate's birthday lunch at Chiswick - kinda fit the set and setting. Birthday dragged on till I can't remember when, but I know the thought of white chinos at night kept me unusually sober.