Questions of the universe

Why is it that water out of the bathroom faucet always seems colder than water out of the kitchen faucet? I've asked a plumber this question and he just laughed at me. Then he stood there for a second pondering the question, and said "I don't know, that's a good question". I think I know the answer to this next question. When my wife makes me a sandwich, it always tastes better than if I had made it myself. I can use the exact same ingredients but hers is inevitably better. I think when I'm making one for myself it's just to fill a void. When she makes it for me, I think it's made with love. That's all I got. OK, last one. What was the greatest thing before sliced bread? Talk about this one during happy hour or over the dinner table tonight and see what you come up with. Please be careful how you answer.