The most annoying thing is the lack of validating machines (mostly because they get vandalised at all times) at minor stations. I remember once travelling from a town in Abruzzo to Rome Tiburtina (what a nightmare of trip, by the way - if it wasn't for the astonishing sceneries I would have been dead by now) with a blank ticket i.e. without any date or time as I could not print it on the relevant machine. The train officer came at some point and wanted to fine me! After quite a long discussion in my broken Italian, he then walked off saying "Same old excuse" or something like that - how rude!