I may be biased due to the source so I thought I'd throw this out for opinions. Last Sunday I rode in the Tour de Cure and one of the rest stops had a mechanic from a local bike store for free adjustments. As I walked up to the table, a cyclist had his bike up on the stand getting his chain oiled. About then I overheard the tech say, "Guy that's a really bad gear combination you've got there" and he went on at some length about it. Noisy, hard on his chain, so much extra friction and so on and so forth. I couldn't resist a sidelong glance at it. It was a road double with the chain on the big ring and the third cog. I didn't see how many cogs the cassette had but I assume 10.
Maybe it's not optimal but I'd never heard that the third cog was "cross-chained" let alone as bad as all that. I frankly thought he was being a know-it-all bozo at the cyclist's expense. But I'd also overheard the tech laughing about struggling "first-timers" and guys who hadn't trained enough which may have colored my opinion. What say you?