objectA = Object.assign(objectA, objectB);
/rant

Several months of work got deployed and suddenly the app stops displaying user submitted images. No new changes that looks related went live and the images seem to be stored and read by the code. Nothing looks odd about it other than images not displaying. 4 hours of frustrated developers later an accidental newline at the top of a routing file is removed and all is fine.

Reading code with no syntax highlighting or indentation is more painful than I thought.

Was helping an intern with testing and he was trying to hit a specific branch in the code and just couldn't get there. Spent probably 20 minutes trying to figure out what the hell was going on since by all reasonable logic the code should run. Getting other developers involved trying to figure out what the hell was going on. Then discovering he was using a stub of the class with the method we were trying to reach overwritten to simply return null. Pretty much just wanted to go on a walk at that point.

I excused myself for writing a switch statement with only one case during a code review with thinking it was likely to get more cases in the future. Lead dev said that's okay, then chuckled a little before he showed me a switch statement with two cases added by one of the people who can bypass the review process: case true and case false.

Waiting for code reviews from the lead dev. Often it ends with a branch sitting untouched for weeks and becomes a pain of merge conflicts.

Spending too much time on smaller decisions sometimes. Spending 5 minutes thinking about naming a variable and such.