Father and Son Vampires

Father and son vampires fly over the village. Father says:
"We will land in this village and suck blood from a few people, then we will go to a next village, and again suck a few people, and then to a third village..."

Son asks:
"But daddy, why don't we land in this village and suck blood from all the people at once?"

Father smiles knowingly:
"Son, we are VAMPIRES, not BANKERS."

Nghe, nghe, got it? What this joke subtly implies is that vampires are better then people working in banks. This is a nice one if you're tired of lawyer jokes...