Spent 6 hours chasing a missing semicolon... it was a space.
I was following a beginner tutorial for making a simple calculator in JavaScript, and my code kept throwing errors. I checked every single line, compared it to the example, googled the error message, and even restarted my computer out of frustration. Turns out there was a stray space in my variable name, so my function was looking for 'my Number' instead of 'myNumber'. Took me a whole evening shift's worth of time to spot it, and I nearly threw my laptop out the window. Anyone else had a dumb typo like this eat up hours? I need to know I'm not alone here.