Around 200 years ago, we all decided to move into the forest, instead of continuing to take our chances on the plains. It was not one person's decision, and unfolded naturally from the fact that (1) the forest provided benefits like shade from the sun, plentiful foraging, and privacy, and (2) we had invented things like strong rope and canvas, allowing us to better use the forest to make houses, and other resources. It started with one family, and then another. It took a long time, but eventually the elder councils proclaimed: "we are forest people now."
Things worked out great! There was a strong impression among everyone that everybody was getting what they needed in the forest, or at least living in the forest was the best of all possible worlds, now that we were in it. Many had lost a lot on the plains because of lions, and the heat. The general trend towards forest life just felt like a no-brainer. Eventually, some people even rationalized that, because we have fingers and toes that easily grab onto branches, we were probably always meant to live in the forest.
There were some pretty early on who argued that we were better off on the plains, or others who (still pretty early on) argued that if we could successfully live in the forest, we should go ahead and try to make the full, dangerous journey through the main basin of the forest, because supposedly at the other end was a beach, with even more resources.
In the latter group, many people died trying to get through the forest, and those in the former group, those who tried going back to the plains didn't do much better. After enough failures on both sides, our forest society was a little shell shocked, and decided to focus on just optimizing forest life.
It took a while, but eventually people realized that the forest, while it was most assuredly the "best" place to be, had problems. There were bugs, and bears, and as we walked through dense shrubs day by day, we compacted dead leaves under us, and created large swaths of compacted, dead forest floor. This compounded into problems of forest fires, as well as the fact that so many dead leaves produce an unbearable ode=or for some. Some areas of the forest burned up so completely that people found themselves living in, essentially, the plains again.
But we could live with these negatives, it was still the best possible world.
Enough time passed, and people started to not remember there was anything other than forest life, and yet ironically, through some unconscious unease, strived to change the forest in their image, to make it more bright, less infested. People started saying things like: "What if we could remove all the leaves from the trees, except for the ones that we know are strongest, and that way people can see the sun again, and the heat will drive away some of the bugs". Others started to be angry that the forest had so many trees, and started saying: "I love the forest, but I wish we could clear out some of this space here to be completely free from the bugs that come so often."
Others started saying: "Why is it that wherever we go in the forest, the forest bugs follow us, the bears still come and eat us?" Some people try to explain: "That is just what a forest is! You can't have your cake and eat it to: if your gonna live in a forest, there will be bugs and bears, if your angry about it, don't blame the forest, we are the ones that moved in here in the first place."
In general, if trying to get through the forest is out of the question, we got to suck it up and realize we live in the forest, and its not going to get any better, but its not the forest's fault, and its not any one person in the forest that is causing the issues. It's just a forest, there is always bugs and bears in the forest.