well some are cause they are caused by a typo : and ; mix one up somewhere and watch a coder go mad trying to figure out what is wrong. And that isn’t even the worst one. the worst one is tab and spaces in some programs.
The worst one of these I ever encountered was a result of an extraneous , in c++. At the time I didn’t know what the behavior of the comma operator was in the language, and it was maddening tracking down the problem.