If you're willing to stand up for the things you believe in, you'll make better choices, and you'll build stronger relationships. But if you're one person on Sunday morning and a different person throughout the rest of the week, you'll be doing yourself a big disservice.
The moment that you decide to stand up for your beliefs, you can no longer be a lukewarm, halfhearted Christian. And, when you are no longer a lukewarm Christian, God rejoices.
So stand up for your beliefs. Remember this: in the battle of good versus evil, the devil never takes a day off...so neither should you.