Good Riddles

Question: A man runs into a bar and asks for a glass of water. The bartender pulls out a shotgun and yells at him. The man thanks the bartender, then walks out of the bar happily.

Why did the man thank the bartender?

Question: You struggle to regain me.
When I'm lost, you struggle to obtain me.
I pass no matter your will,
but I'm your slave to kill.
What am I?

Question: You create your own Where's Waldo game on a piece of paper. You want your friend to find Waldo but they think you might be pulling a prank on them by not putting Waldo on the paper at all.

How can you prove to your friend that Waldo is on the paper without ruining it for them?

Question: What goes next: 4,7,93,12,9,8,?

Question: There are several different kinds, but the one you pick doesn't do its job.

What is it?