I Have a Question: Why do Restaurants Put Lemons in Water?

I hate lemons in my water. Especially when they are huge slices. I can deal with a thinly cut layer, but for the most part, I like my water to taste like water. Last night I was served a big glass of water in a plastic tumbler and there were four lemon seeds floating around between the ice cubes. I wondered how much an average restaurant spends to add lemons to tap water. Seems like a great way to cut costs. Waddaya think?