You can't get a Big Mac in India, where McDonald's restaurants do not serve beef or pork out of respect for people's religious beliefs. You have to settle for a Filet-O-Fish or a Maharajah Mac--a sandwich made with chicken. You can, however, get a Big Mac in Costa Rica, where you can also try something called a McNifico, which is a cheeseburger with lettuce, tomato, and mayonnaise. But I'm fairly certain that despite some small differences in menu, every McDonald's in the world has a lot in common with every other McDonald's in the world.
Consistency is important in the fast-food business--and in living our faith. The problem with most of us is not that we are bad Christians; it is that we lack consistency. The servant who gets drunk and abusive while his master is away is probably not all that bad of a servant when his master is at home. But he should carry out his master's wishes all the time, not just when he is under his master's watchful gaze. Similarly, if we are to be faithful to our calling as Christians, we have to be kind even when people are not kind to us; we have to defend human life even when that life is not innocent; we have to help those in need even when it's inconvenient; we have to go to mass even when it's boring.
Consistency in living our faith is not too much for Christ to ask. After all, he is perfectly consistent in the love that he has for each of us.