Mama's House

Why is it a slice of lemon in a glass of water? Why not a slice of something more delicious to put in that glass of water cheap-asses order at a restaurant in place of a real drink? Putting aside that restaurants might be trying to discourage rather than encourage the ordering of waters, why don't they put something in there like a delectable slice of orange instead? I mean if you had the option of biting into a nice juicy sweet wedge of orange or a sour wedge of lemon, you would go for the orange wouldn't you?