In the movies and on TV being hit hard enough in the head to be knocked out doesn't cause much more damage than going unconscious, and it only takes one blow.
Someone close to me was mugged last year and took 3 blows to the head with the butt of a gun. Not only did it not knock her out, but she bled profusely, had to get stitches and was in pain for weeks after with headaches.
Every time I see this gimmick used to incapacitate someone I think 'cheap plot device'.
Also - smart, beautiful, thin people and/or incredibly smarter than everyone else people who just know things and figure things out immediately to the awe (and respect) of those around them.
In reality most people are rather plain, heavy and even the incredibly smart people have to argue and/or fight for respect of their ideas from those who just want the credit.
Quiet, unseen children OR obnoxiously bad behaved children and lots of them and babies that require almost no attention from the parents.
They can't show real kids because child actors can only act for so long each day and are only so good and can only do so much drama - but it still bugs me to have a adult centric sit-coms where the people have kids that are NEVER seen and when they are they are quietly eating breakfast or watching TV. (Everyone loves Raymond makes no sense when it comes to their kids)