It seems to be much less common these days (probably because smartphones make it easier to look things up), but there are assorted news stories about people being accused of counterfeiting or even arrested for trying to pay for things with $2 bills.
I had a funny experience with a French cheese shop in SF for this - I tipped a $2 bill and he called me back in confused thinking it was fake, but was good natured when I showed him it was real.
Last time I was in Mexico (walked across the border so many Americans in the area and they list prices in both us and mexican currancy) I paid with twos because that is all I had, which really confused the clerk, but her manager had no problem.
I had to go to El Salvador for a work trip a while back and brought a bunch of fresh $2 bills with me. They use USD as the currency there, but they're constrained by what's in circulation. I thought it would be fun to have my $2 bills there for maybe years, I'm not sure if they have any others!
It’s crazy that Canada, being so similar to the US, got rid of the 1 and 2 like 30 years ago.