On trail you have a lot of time to think about... anything.
There are lots of different people on the trail and each carries a burden. Each person suffers in their own way. Some days they suffer more, some less. They all carry different burdens—some heavier, some lighter, but they all have them. I once met a person who carried a bear canister from Campo to Idyllwild, a stretch of desert where there are no bears. I met another person who carried a full, ten-pound medical bag, but couldn't stitch up his accidental, self-inflicted wound on his hand brought about from pounding in tent pegs with a massive knife . Some of our burdens are useful, most are not.
We all decided at some point what we must carry. Some carry too much and have a difficult time letting go of the things they don't need or never use. Other have burdens that are light, but only because they let go of useful things too quickly.
It is often said that on trail you pack your fears. If you are afraid of running out of food, you pack six days of food for three days of trail. If you are afraid of cold, you pack a -10° F sleeping bag for hot summer nights. I can often get a glimpse of what a person's fears are by how much they carry and what they carry.
Fears become burdens.
After thinking about all of this for a few days, I realized that if you pull back the visible layer of life, what you might find is the trail—the journey we all make from our beginning to our end. And we all carry our burdens all along the way. We pack our fears. We don't let go. We let go too easily. We hang onto unexpressed thoughts and useless ideas. We pack them them away and carry them in the hope that someday they will be useful. But that day never comes and we carry the burdens anyway.
Some of our burdens are useful: love for family, the hard work of maintaining friendships, hope. Others are not: envy of others, fear of failure, pride.
The trail sifts through our burdens and presents them to us under the starkest of lights. It lays them all out. You can put them back in your bag, or toss them in the hiker box. As they say, "Hike your own hike."