Our Habit of Putting Ice in Beverages and Refilling Water

Why is it that whenever your go to a restaurant, they put ice in your beverage?  Is it to keep it cold?  The beverage is already refrigerated and cold ahead of time so why does it need ice?  The ice just dilutes the taste and makes it watery.  Do restaurants fill the glasses with ice so they don't have to give you so much of the beverage?  This doesn't seem to make sense either because ice itself has a cost either by making it or buying it.  Also most places will give you free refills on drinks so that cancels out that theory.  Do people really need their beverages to be ice cold?  I for one prefer beverages without ice and I think we need to start getting out of the habit of putting ice in everything when it is unnecessary.

On a related topic, when you are at restaurants and you have your standard glass of water, some places have servers going around with a pitcher of water constantly trying to refill your glass.  Were talking about glasses that have maybe 24 ounces, plenty of water for 1 meal, yet they have people going around trying to refill these, without asking mind you.  One glass of water is enough.  I don't need it to be full throughout the entire meal so that at the end of the meal I am left with a full glass of water.  If people need a refill on water, they can ask for it.