You can compare involvement of jewish observance with sports.
There are some people who go to shul every single day, lay tefillin, and are super stringent about halacha. Similarly, there are people who see every single last game, memorize seemingly endless statistics, and get the shirts.
Then you have people who go to shul on Rosh Hashana and Yom Kippur, who think that kosher wine can only come in a Manishevitz bottle (blech) and who don't know that Succos is a holiday too. Tee Hee. Similarly, there are people who more or less watch just the Super Bowl or the World Series and don't think about the existance of the sport otherwise. :)