Wanna annoy a programmer?
Next time you're filling out a form, put a single ÿ at the end.

It's not very commonly used in text and it's 255 in decimal and 0x00FF in hex which feels like something is broken if they go and investigate.

@olafurw just rеplаce аll fitting lаtin lеttеrs with similarly lооking Суrilliс lеttеrs.

Like I did in the previous sentence.

@olafurw which reminded me that in the times of #FIDONET the editor would break on Cyrillic “y”, and we had to replace it with latin y everywhere.