[spoilers] Harry and Ruth. The Wonder Years.

[Silktie]

In my defence, I didn't forget that there was such a thing as the Havensworth scene, I just forgot that Harry didn't have his tie and jacket on...

I assumed the denim shirt was just something she kept at the office for emergencies, such as when your outfit for the day gets ruined by little things like ink or tea spillages, or you know, by being blown up or kidnapped and drugged. But since we've discussed Harry's longer hair as a possible conscious wardrobe choice to show the character's inner turmoil, I think you may well be right that the denim shirt was meant to say something about Ruth's state of mind.