Yes!!! The edges of items that cross frames are really exasperating: how many pixels of a bus image have to be in a Recaptcha adjacent frame before the app figures yeah that's "also" or "still" a bus? When I have to spend more than 2 seconds to get out of the challenge, that sort of thing is usually part of the reason.
I can be pretty literal minded sometimes, so I often have trouble with the Recaptcha challenges that ask for things like "street signs" or "traffic lights"... is it just the sign, or the cables and poles they hang on or sit on... that's usually when I either refresh the thing hoping for "store front" or else just curse and figure I didn't want to log into that site today anyway.
Somewhere I read that there are certain circumstances where recaptcha modules can be set to deliberately make images grainier or anyway tougher to meet the challenge. This could be for instance if you frequently clear your browser (which of course then means if you do revisit a site and have cleared your credentials, you'd have to log back in). Apparently frequent logins to the same account can make the module think you might be a bot so Recaptcha doubles down and asks for another go-around or fetches up fuzzier pictures.
That seems pretty ironic, since clearing a browser is often a security-oriented suggestion that many sites offer up when you're signing out of a banking or billpay session etc. The other irony is that bots have apparently become better than humans at fishing images out of murky backgrounds.

The darn bots probably spend all day practicing on Google's humongous universe of pictures of everything.