I have to confess to getting mildly annoyed when, on the same route, the timing of ticket checks varies too much. I usually travel with XC from Birmingham, so it's after a crew change, and depending on the crew a ticket check could happen while still in platform (rare, admittedly, but it's happened a couple of times...), shortly after departing New Street, after Wolverhampton, or at some arbitrary point between the above.
This is an issue because I almost always use the mobile ticketing app, so there's no ticket for me to just 'leave out' and I like to pop in my headphones and close my eyes to relax. This leads to minor frustration for both me and TM alike when I've drifted off into my own world thinking the ticket check will be at 'X' because it wasn't done at 'Y', only for it to be done between and the TM having to nudge me and wait while I fumble to unlock my phone and bring up the app.
Basically I imagine I'm one of those people who is unintentionally a bit of a pain in the rear end when there's a train full of passengers to get through.