"Most memorable bug you fixed?"

A recent instance happened in one of my Scratch projects, and the bug involved "Infinities."

I had an opportunity to teach kids programming, and it involved Scratch. So, to have something to show those kids at least, I decided to make a small game.
In that game, I had an object that takes some time before appearing after being cloned (i.e., instantiated.) The duration was calculated by dividing a constant with a variable:
[Wait for ((3) / (variable)) seconds]
The bug is that I forgot about the case where 'variable' can be 0, which is classic and insignificant.

Well, the thing is that I learned two things the hard way:
1: Scratch is very flexible about integers and floats (e.g., at one second, it looks like an integer, but one operation later, it's a float.)
2: Scratch does not provide any 'runtime errors' that can crash the project.

In other languages, similar "wait" methods take "milliseconds" in an integer, so it would have barfed out a "DivideByZeroException" or something. But Scratch was so robust against project-crashing behavior that it literally waited for f*<king "infinity seconds," effectively hanging that clone without warning or runtime errors. This masked my bug. It took way too long to debug that s#!+.

Don't blanket-mask any errors.