The definition of tolerate is to allow the existence, occurrence, or practice of. Another way of defining tolerance is being Christ in a given situation. It's knowing what you believe and not being hurt by someone else's beliefs.
I think so many of us struggle with tolerance because we are lacking confidence. We need the recognition to know we're not wrong. As a result, things become vague such as "Happy Holidays" rather than "Merry Christmas" or "Happy Hanukkah." Things like "Happy Holidays" show's zero diversity and culture. It makes things very bland rather than allowing people to show their true colors. A tolerant person is able to walk down a street and see a menorah on one house and a nativity scene on another house and think "God is awesome!"
There's no need to get upset for what someone else believes. Be confident in who you are and what you believe. Share your beliefs with others, not to convert them, but to learn more about different points of view in order to sharpen yours...let's face it, no matter how much we think we know it all, we don't. There is always a chance to learn.