The Cliché: Despite going hammer and tongs at each other for the majority of the movie, and despite the many, many rounds of ammunition spent on seemingly trying to kill each other, if the villain finds himself in a prone position (hanging off the side of a building is the most popular scenario), the hero will almost always attempt to save his nemesis. Make up your damn mind, can't you?
Examples: Batman is particular guilty of this cliché, but since he's taken a vow not to kill his enemies, we'll give him a free pass. Clint also offers a rescuing hand to John Malkovich's killer in In The Line Of Fire, noting that although he doesn't want to, it's his job. It's even possible to have it both ways, as proven by Eliot Ness in The Untouchables, who spares and then kills Frank Nitti.
It really jars in Daredevil, however, when the titular hero spares the villainous Kingpin after killing practically every henchman and underling he comes across. Talk about double standards…
If It Was Real Life: For starters, catching somebody by the wrist is much, much harder than it looks on the big screen. Most of these moral quandaries would never come to pass in the first place!