My mug collection is...eclectic to say the least. There's a "World's Best Husband" and a "World's Best Boss" mug. I've got about eight from various public radio fundraisers. Then there's, like, two matching Crate & Barrel mugs. The lesson here is that to be an adult is to not have a matching set of mugs.
That's why I'm borderline obsessed with Pigeon Toe Ceramics' (badass female-owned Portland studio) Simple Mugs. No matter if you buy one or several, any combination is winning without matching. The specialness of these products has to do with the fact that they're all handmade, but also that each glaze isn't quite an ordinary blue or green or even millennial pink. The ultimate goal, I think, would be to eventually own this entire set and to embrace the idea of never having two of the same anything.