I had a discussion with a friend recently and during that discussion, one comment was "Fitted sheets are really both the best and the worst", of course referencing them as awesome when put on a mattress and the worst when you're trying to fold them.
What else do we have that would qualify for being awesome, but also the worst in a different context?
To be fair it was the NSFW tag that gave me the idea. I went "why would this have an NSFW tag? … Ooooh!"