You are not in control
Focusing on the things we don't have control over will make us lose sight of the ones we do.
We try to fulfill our responsibilities, whether they are work, university, school, etc. We do what we can to do a good job and have everything turn out "as planned". We feel stress and frustration when things don't go our way and maybe we think we did something wrong or didn't try hard enough.
The reality is that most things are not under our control and they are not going to be. Many times we simply have to trust that things will turn out well and that our plans will follow the course we have planned for them. Allowing ourselves to let our surroundings do their part can give us the peace of mind and drive we need to fulfill the things that are up to us. The world flowed in its own way before we were here and will continue to flow when we are not. After we do everything in our power to get what we want, letting the things we don't control do their part can give us the peace of mind we need.