I don't have the means to over give and would be very selective if I did have funds to be generous. I have read that some charities use very little of charitable money for the cause and most of it is eaten up with administrative funds. What I give I give locally because I know where it is going.
It's an interesting theory. I, too, am generous to a fault but I try to gauge my giving. I believe that all of my money actually belongs to God and that He'll nudge me when I need to give - or offer. I wait for that voice and I also try to see if it is a need or a want that I am trying to fill. I also believe in paying it forward, not paying it back.