I really don’t want to be that person, but ever since Cas let slip he doesn’t like Dean’s ‘lumberjack’ look, Dean’s stopped wearing plaid around him (Sam hasn’t, because why would he?). I mean, I don’t know what happens in between episodes, and apparently a lot does, but on screen, every single time Dean’s been with Cas after Rock Never Dies he’s chosen to wear a ‘normal’ shirt.
The only exception is S12E12, but, whatever, I’ll forgive that episode anything.
And, of course, for the purpose of this post costumes don’t count, so I haven’t included suits or anything, but just as a reminder, this is what Dean changed into after Cas’ bad-tempered comment - and I’m willing to bet half my liver those were not random clothes he had in his duffel - he went out and bought them, because lumberjack? I’ll show you who’s a fucking lumberjack. Dick.