Ok, I got 10... if not-smiling-physically-but-smiling-mentally counts.
I guess that's because I already know some of these pictures or similar.
Also the fact I played "Theme Hospital" quite a bit a few years ago made some of these pictures look 'old' to me
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(if you don't know "Theme Hospital", it was a humorous game where you manage a hospital... and sounds like "Please don't die in the corridors. Thank you." from the megaphones were common
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).
As for the hand granade, I guess it could either be an intentional joke, or maybe someone did not know the word 'extinguisher' but he thought it looked like a hand granade, so he decided writing anything was better than writing nothing.