"In the privacy of your own home." As opposed to what? The privacy of someone else's home? You have no privacy in someone else's home; that's why you have your own home.
"Down the pike." "He was them meanest guy ever to come down the pike." Fine. What about guys who come UP the pike? Now everyone lives "north of the pike." Some guys have to come up the pike, and they're really mean, because nobody mentions them at all. And what about a guy who doesn't even use the pike? He arrives on Amtrak! "Boy, he was the meanest guy ever to arrive on Amtrak." Doesn't sound right.
"Open a can of worms." Why would you have to open it? Are there really sealed cans of worms? Who sealed them? Worms are usually put in a can after it has been opened, and emptied of something else, like corn or pumpkin meat. Uncover a can of worms, maybe. But not open.
Why do we say "out like a light?" The primary function of a light is to be lit, not to be out. Why choose a light to represent the concept of being out? Why not, "On like a light?" The same is true of "Dropping like flies". The wrong quality is being emphasized. Flies are known for flying, not dropping.
And let's forget "Meteoric rise." Meteors don't rise, they fall.