There is a common saying, "Don't worry about what you can't control". I googled to see if there was an originator of the quote to give credit to and it came up as Tim Tebow. I am doubtful that he was the first to say it.
Nonetheless, I think this is generally a good rule to follow. It sounds simple enough, but the hard part is determining the lines between what you can and cannot control.
For instance, if I am negotiating for a house and it is listed for $10 but I really want it for $9 even though it may already be the cheapest house in the world (actually it is not), I cannot control your willingness to sell me the house at my desired price. That said, it is hard to argue that I could not influence your willingness based on my ask or method of negotiation or a number of other things which I can control. To demonstrate, if I were to say, "I will buy the house for $10", it is safe to say that my chances of getting it for $9 would be lower than if I were to say, "I can offer you $8", in hopes of receiving a counteroffer. It is important to note that I cannot control your decision but I can influence it through choices that I can control. By Tebow's rule, I should not worry about your decision, but rather, about my choices that could influence it. That sounds like a sound approach to me.
A less ambiguous example is the infinite number of things that have already happened in the past. I cannot imagine a good argument to suggest anyone could control the past, but you can certainly control how you choose to move forward from it, or even how you choose to remember it. You may not be able to change what actually happened but you can control choices which can change some of the influences that come from the results of the past.
Despite the fact that we often lack absolute control, we have these constant choices that we can make every day which can influence things or change the influences that things have, on ourselves especially. I believe that we (myself included) forfeit most of these choices to the defaults of the systems that we live in, while at the same time, we suffer from wishful thinking that we can control a lot of things that we cannot.
In short, I think we tend to underestimate our choices and the power that they can have while overestimating our control over things we cannot have any over. I might even go so far as to say that our control is limited exclusively to our choices, but our choices are so expansive that we mistake the impacts and influences that they can have for illusions of control.
A good rule of thumb, I think, is to focus on the choices we have when we feel the need to change something that is out of our control. You may not be able to change that thing, but you can change something.
