I find it ironic that, although I use too many semicolons when writing English, I quite often leave them out when writing code. Which is the greater sin? I suppose it depends on which social circles you run in.
The Strunk-and-White crowd would likely be more offended by my overuse of the semicolon. They might also object to the grammar in my “social circles” sentence. As the old saying goes:
Run in is better than run on, unless you are ending a sentence with run in; everyone knows you don’t end a sentence with a preposition.
I like very much that the old saying uses a semicolon. It puts the Strunky/Whitey folks in a tough spot.
As to my other bad habit (omitting semicolons from code), it usually means my code doesn’t work. I spend hours “debugging” (read: swearing at my computer) before I pinpoint the problem.