The "worst" that I can remember was actually a Django quirk - ORM result sets (or QuerySets as they call them) execute their query at object evaluation time rather than at instantiation, so unless you cast your resultset to a list it won't actually talk to the DB just yet. Now attach a GUI debugger such as PyCharm/IntelliJ - it will internally evaluate every expression immediately (to populate its GUI) and cause the behavior to diverge (it will "fix" the code and behave as you'd expect when ran under the debugger).
I guess there could be certain contexts (system programming? low-level libraries? etc) where these are going to be an issue but when it comes to web/API or business logic development I haven't encountered these.