Empty coffee cups. I hate it when someone has a paper coffee cup and it is just obviously empty. Can’t they at least put some water in it?
Cop/detective shows in which the lead is having a conversation with a (usually) non-police friend or family member about something totally mundane. An offhand remark is made, and there is practically a visible lightbulb over the detective’s head because something that was said give them the exact connection they needed to nail the bad guy.
I’d seen this decades ago on TV and heard it on radio drama. Secondary character has been corresponding with an old school friend or a pen pal and has exaggerated about how successful they have become. Now friend/pen pal is coming to visit and secondary character has to get main character to help them make the lies look plausible, or get the main character to cover for them as they run away so as to not get caught in the lie. The lie has now morphed into phony pictures on dating websites, but it’s a little harder to cover that up, unless the real person from the photo is willing to play along. Ha, ha.
Donald Bellisario frequently had the dumb blonde who is constantly doing dumb things that endanger our hero while he is trying to stop the bad guy or help her escape. Completely ignore instructions given by the man you want to save you, and then stumble around, apologizing profusely while making everything worse and giving our hero a few more scrapes and bruises.
Very intelligent people are always socially awkward or hateful to anyone not as smart as they are (which would be everyone, of course). The Big Bang Theory has made it work for over a decade, but it’s played for laughs in shows that aren’t comedies. Dr. Temperance Brennan in Bones comes to mind. Going far back to a show that featured a genius misanthrope and a clumsy, dumb blonde, Probe with Parker Stevenson.