It would be okay with me if no one said these things ever again:
Dive bar
Gluten-free or, really, even just gluten
Partner in crime, unless used to describe an actual accessory to a legal violation.
Oh! I just remembered this one three days later. Midcentury modern.

And, while we're discussing terminology, here's a question. Is the whole thing still called "online dating" if it takes a great deal of time and emotional wherewithal, but does not result in any actual dates? I think it may be time to coin a phrase.