A Protestant moves into a Catholic neighborhood. It's a pretty open-minded and welcoming community, and everyone gets along great.
The first time an issue presents itself is when Lent rolls around. During Lent, the Catholics in the neighborhood all swear off red meat. Every day at lunch, however, as his neighbors were eating cold tuna sandwiches, the Protestant would grill himself a big, juicy steak that could be smelled throughout the neighborhood.
Several weeks into Lent, the Catholics meet after Mass to discuss the issue. They didn't want to be unneighborly, but the smell was really driving them crazy.
Then, one of them comes up with a suggestion: since the Protestant moved to a Catholic community, maybe he'd be open to converting. While it wouldn't fix the problem that year, it would make next year's Lent go much more smoothly. After much debate, they agree to bring the offer to the Protestant.
To their surprise and delight, he is completely open to converting. He goes through the process and gets rebaptized as a Catholic. The entire neighborhood shows up for his confirmation, where the priest splashes him with holy water while saying, "You were born a Protestant … you were raised a Protestant … and now you're a Catholic."
The next year goes smoothly, and the whole neighborhood gets along great. Then, Lent rolls around again. As everyone is at home with their cold tuna sandwiches, a smell permeates the air: charcoal, wood chips, STEAK. Confused, everyone rushes over to the convert's house.
They find him standing over his grill, a juicy steak cooking away. He's splashing the slab of meat with beer, and the neighbors hear him speaking in a solemn voice.
"You were born a cow … you were raised a cow … and now you're a fish."