I DM’d a group that tried to optimize every situation, and every turn off combat. That’s okay as long as it stays fun, but once they start spinning their wheels, or one player turns combat into a slog, then I take measures.
In my experience (and from what I’ve heard of other groups) optimisers are rarely the cause of this problem, usually it’s the more casual or inexperienced players.
The rope mimic has some more specific tastes.