Can someone explain what's up with the memes that start with "Nobody:"

I don't understand the "Nobody" part, especially since in most memes it's just blank. It makes sense when "Nobody" was saying something that most people disagree with, eg:

Nobody: I love slamming my fingers in a car door

Ford: New F-150 now comes with a dedicated finger-slamming door

That would make sense. It's a joke about someone being out of touch with popular sentiment. But the ones where it's:

Nobody:

Optimus prime taking a bath: Ahh, my electronics!

It seems like the nobody part doesn't relate to the meme in any way, except for being a common format for presenting things.