Bumps.

I spent my Saturday doing the last thing on earth a Floridian would ever do with the inside of a tire: sliding down hills of snow.
I've got a few brand new purple bruises (mostly on my knees and hip bones), and a lot of good memories.
I guess inner tubing is kind of like life:
You climb up to the top of this hill, and then you slide, slide, slide down.
And on the way down there are lots of bumps. Sometimes, the bumps are good, and you fly through the air, and when you land, you laugh.
Sometimes the bumps aren't so good, and they kind of throw you off your tube, and when you land, you hit your face on packed ice, and maybe you lay there thinking: what happened? The last time, that bump was fun. The last time, that bump made me happy.
And maybe someone comes careening toward you while you're facing in the other direction, and their sled hits your inner tube, and you come crashing down and slam (again) into the ice.
But then, you get up, and you brush yourself off, and you move out of the way (because you've learned your lesson) and you start your ascent back up to the top of that hill.
And as you climb back up, slipping and sliding your way up, you wonder if the next trip down will be one that ends in laughter or in bruises.
Either way, you're glad you did it.