It is nice to treat your friends.
Dave Mike and Bill are at a restaurant when the waitress brings the bill which is 60 dollars total.
Dave wants to decide how much to pay.
Dave throws in 75 dollars and tells the other two not to worry about it as it's his treat.
Dave throws in 20 dollars and another 3 dollars for the tip in the middle of the table.
Mike and Bill are delighted that Dave is such a good friend and are happy for the gift of free food.
Mike and Bill also pay the same amount each and nothing particularly interesting occurs.