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 I've always thought that an "@" character in an SMS should break something somewhere sooner or later, but I've never seen it happen myself.

[Its value is zero.]

@TimWardCam @olafurw Twitter (like original SMS linked kind) burned down those bugs decades ago.