It wasn't until I went to college that I realized that there is such a magical thing as a tree hole in the world. People post all kinds of things anonymously in tree holes: there are confessions, breakups, lost and found items, missing persons notices, some are happy and some are sad, and you can vaguely see all kinds of life behind the various Weibo posts. Those words that I dare not say in real life, those unknown feelings, are fully revealed in the tree hole.