I came across many images on Twitter like this
update 1
Original link.
Does the hat resemble nation? If yes then what's the reason?
I came to know that everything that ends with nation or sounds like nation they use this sticker and laugh at it.
But I don't get the joke.
Best Answer
The joke is that this is a parody of another popluar meme. From knowyourmeme.com, What in Tarnation,
"When you find a city slicker on FarmersOnly.com / wot n ternation"
The meme above spawned many parody memes. Here are some of the memes.
Notice that the parodies have the hat in common, follow the formula what in X where X rhymes with tarnation, and the image is somehow related to X.
In the OP, notice that the image is of a bee, bees pollinate, and the act of pollinating is pollination.