Bob: I’m a real football fan.
Ray: Yeah? That’s funny, I never hear you talk about football.
Bob: No, I don’t talk about it much. Hardly ever, in fact.
Ray: Do you go to many games?
Bob: No, I rarely ever make it to any games. Weekends are so busy.
Ray: Oh, so you must watch a lot of football on TV.
Bob: No, rarely ever. I’ll see it once or twice a year when someone else has it on.
Ray: Read about football? Look it up online?
Bob: Nope.
Ray: I thought you said you were a football fan?
Bob: Oh, I’m a fan.
Ray: How can you be a football fan if you don’t go to any games, talk about it, watch it, or read about it?
Bob: Mom & Dad were both football fans, and I grew up in a football household. I even joined a team once when I was a kid. I just don’t want to go overboard with this whole thing and let it interfere with my life, you know?
Ray: Are you really a football fan? It doesn’t seem like it.
Bob: Oh, I’m a fan.
Now, how absurd is that? I can tell you how absurd……go back and change “football” for “Christian” and you’ll see how absurd it is for people to think they’re Christians when they do not talk about Jesus, read about Him, or go to church except on some occasions. How can such a person be a Christian?
Thomistic Bent 
There are many people today that call themselves Christians for many different reasons, very few of which amount to true Biblical Christianity. God and Christianity end up being whatever you want them to be. Today’s culture takes what makes them feel good and live a good life and they call it Christianity because they heard it in a Church and said a prayer when they were a child. As Paul Washer says, everybody wants to go to Heaven, they just don’t want God to be there. You can call yourself a Christian all day long but it doesn’t make you one.