Demo is used as an abbreviation for both demonstration and demolition. Usually it's pretty obvious which one is intended, but every time I hear someone say "demo" I try to imagine what kind of chaos would result if the wrong usage was assumed.
Had a coworker whose first language was not English. His English was good, but some coloquialisms went over his head. At one point, I had to explain the difference between a "butt dial" and a "booty call."
Anyway, there was once a joke on Friends, where - to massively paraphrase - Joey said 'the point is moo ... not even the cows care about it'. I sometimes use 'moo' instead of 'moot' just 'cos it amuses me.
During a cycling workout, the instructor said “our destination is breathless” as a motivator to really push hard. I thought she said “our destination is breakfast” and honestly, I prefer my version.
I had to look up what was wrong with it and still it seems like a very minor difference. But hey, I spend my time playing video games, who am I to judge what is worthy of one's time.
My Polish mate, who's English was pretty good but still had a noticeable Polish accent, was asking me about some weird pronunciation of a word or I corrected him in something.
He said "Ah Potato, Tomato. Doesn't matter". I burst out laughing, some guy actually tried to correct him on it.
I also like "We will burn that bridge when we get to it".