Here's some things I learned on a backpacking trip in the Sierra Nevadas recently out of Lone Pine (Cottonwood Lakes area just before New Army Pass).
Snowshoeing through a boulder field covered by 4 feet of snow is a pain in the butt. I had to put on and take off the snowshoes every two steps. The snow gets undermined near the boulders so even with the snowshoes, you fall through and get wedged against a boulder (messing up your knee and ankle). It is better to avoid the boulder field all together and climb the nearest hill to a point where the area gets more sun exposure and walk or boulder hop across.
After a day of falling through soft, wet snow on a backpacking trip, your only pair of boots will freeze solid and you won't be able to put them on. Putting a backpacker's towel in each boot along with a 1 liter Nalgene bottle full of boiling hot water will solve the problem. The water stays in the bottle. The hot water bottle will defrost the boot and the towel will absorb any defrosted water so it can be removed without refreezing or making your feet colder.
A 0 degree sleeping bag from Walmart won't keep you warm in the 20s, especially if it's too short, the hood doesn't close enough, and the zipper on top of the bag opens while you sleep. However, a 1 liter Nalgene water bottle will keep you toasty warm for 3 hours.
Spindrifts are demoralizing events that can get you to turn around and go back. They are basically ice tornadoes. If you get in the middle of one, you'll be pelted with snow and ice. They also wipe out footprints so you can't see where the trail leads or where you came from.
Backpacking in the snow is colder if you go somewhere that doesn't allow fires.
With enough wind, a candle lantern can be put out in a 4 season tent just by the wind swinging it around too much. The wind was unable to directly blow out the lantern in the tent. It went out twice in an hour.
The best gear in the world is no substitute for knowledge. Knowledge will help you realize the limits of your gear so you don't get killed using it.