Once in a lifetime is sooner than you think.
So why waste this one day, this one moment on the mundane, on the things that don't matter. Why sit back and let the world spin around you, when you could be out there spinning with it? Why always sit back and wait for something else to happen, for the "right moment"? There is no right moment. There is here and now. Take the chance. Jump in. Make mistakes. Get messy. Have no regrets. Don't let this time slip away. You don't want to wake up in 5, 10, 50 years and think "I wish I had...." or "I should have..." Today's the day to do it.
Make it count.