Surely, somewhere, this has been said:
A preacher, in his sermon, had called on church members to give a tenth of their income to the church.
After the service, two members were discussing his message outside.
The first said to the second, "The way the Lord has blessed me and my family, I'm not going to give just a TENTH! I've decided I'm going to give one TWENTIETH!"
Startling fact: giving would actually go up in churches if members did give 1/20th of their income.