Two things:
1. To feel like a kid - I LOVED walking in the bush at my grandmother's place between ages 7 to 13. Played all sorts of games there, built hiding places, climbed trees. Explored every nook and cranny of the area. Built elaborate underground shelters and some in trees. It was a team effort and we all loved it. Being in the woods and setting up camp is the only way I can relive those memories. It's the absolute best time I have and I love it.
2. To be away from problems - modern life has fabricated all sorts of problems that wouldn't be there if we lived in a more simple time. Is my career choice good, how are my relationships with my colleagues, what gadgets and clothes do I need, what would I like to do in life, do I spend too much time online, what to make for dinner today, I don't like waking up so early and so forth. These are all first world problems. Bushcraft takes them away. You wake up when the sun comes up, eat what you have, make due with what you have, enjoy the time with the people who are with you and do physical work. It is a fabulously simple way of living for a couple of days at a time. The more you have to worry about essential needs the less you have to worry about what you like and don't like. There just isn't any time. I embrace it and love it.