My take on money is that it is a gift from Allah to be shared and used wisely. I have been blessed with more than I or my family will ever need so I focus a lot on ways to pass on the money and share it around and try to ensure it is used for 'good causes'.

I don't see it as mine, mine, mine!

One of those ways is tipping people. I can't see anything wrong with that. For me it'a way better feeling to give than to receive.