There were quite a few things out there that I just messed up. I don't know if I was just misinformed or stupid but I swear that my mispronunciation of the word 'odyssey' is entirely not my fault. When I was 7 or 8, there was this Lego commercial advertising a new playset and I swear it was called Undersea Odyssey or something like that and the announcer guy pronounced 'odyssey' ah-DEE-ah-say. So for several years afterward I pronounced it ah-DEE-ah-say. Luckily, the word 'odyssey' rarely comes up in conversation or I would've really looked and sounded like an idiot.
Those are the two main learning problems I've had that I can recall at the moment. I'm sure there are others but those are the two big ones. While an odyssey faux pas has never happened, I did accuse a girlfriend of cheating when she had an acne outbreak around her mouth. I thought that was odd because she certainly wasn't performing that on me. I can't explain how embarrassed I was as I told her my reason for accusing her (which when you say it out loud, sounds really ignorant). She then went on to tell everybody else.