Genius Bonus: Reverend Lovejoy tells the congregation, "And once again, tithing is ten percent off the top. That's gross income, not net. Please, people, don't force us to audit." This is both a religion and math joke. In Christianity, it is customary to give ten percent of your weekly pay to the church (see Genesis 14:20, among other verses). The congregation was spending all their paycheck money and then whatever was left, they were taking ten percent of that to use for the offering. Which, naturally, would be a ridiculously small amount. No wonder Lovejoy was annoyed.