Expectations & Burning Out
What I'm about to write is taken from personal experiences and mistakes. I'll try to give two main examples in order to be as relatable as possible: one from business and one from life. The TL;DR for business: be a supercar with a clutch.
Business
When starting a business there is a fundamental truth: you try to optimize the happiness of your customers. Trying to achieve this goal, however, can consume you until there's nothing left, just an empty shell doing mindless tasks. You can't let your happiness be dictated by the ups and downs of your business. You should have a solid baseline that never gets affected. Let me emphasize that: a solid baseline that NEVER gets affected. A depressed founder achieves nothing for himself or for his customers.
In my case, every day that passed felt like a boulder on my back that I had to push harder and harder, as I worried about what my customers were thinking about the delays in delivering the two hardware products I was producing. Hardware products are hard, time-consuming and, most importantly, unpredictable. War breaks out? Your supply chain is disrupted and your packages can't arrive anymore, or arrive with huge delays. Choose the wrong supplier and you lose a month chasing after them. I felt helpless as the boulder got heavier: my eyes started looking at the ground and I lost the ability to see the future. This was not depression, it was an inability to detach my own meaning from the product I was creating, and an inability to control my own expectations while setting them equal to my customers'.
So what were the real expectations of my customers? For one of the products I found people who were understanding and had absolutely no rush to receive it. For the other one, they thought they needed the product urgently, but then waited three months to take it out of the box.
My expectations were higher than either group's, which is logical. For me the businesses were my life; for them they were something they bought. Was it worth it to have my expectations demolished day after day as problems continued arising? Absolutely not. It did not drive me to work harder; it just removed the fun from working.
What solution do I suggest? Using your clutch. Being obsessed with something you are creating is what distinguishes you from everyone else trying to do something similar, but when problems arise and you're about to snap, use the clutch. Thirty minutes before sleeping, use that clutch, help your body rest. It's obviously easier said than done.
Life
This one might be a bit hard to explain, but I'll do my best. I stutter, or at least I do when I lose control of my emotions. I have stuttered for as long as I can remember and controlling it has been difficult. For what I am about to say to make sense, stop for a second, close your eyes and go back to a time when you felt embarrassed in front of others. Maybe you were underdressed, or you had done something stupid and thought everyone was laughing at you. Now imagine feeling that every time you talk to someone, not knowing whether you will be able to control it. By now you are thinking: it is not that bad, you got used to it. The short answer is no, you never do.
With that intro out of the way, you might understand how harmful expectations were in my life: they affected who I talked to and when. My solution? Well, I don't have a real one, apart from trying to control your own expectations and not projecting your fears and thoughts onto others. If you're able to do that, you might have a real shot at solving maybe the biggest hurdle holding you back. This really applies to anything, not just stuttering.