NOTE: Real names obfuscated.I'm walking to the office trying to calm my racing heartbeat. I have tunnel vision. I can't think beyond the conversation I'm about to have. I have to fire an employee; something I've never done before. The decision to do this has been in the back of my head for a long time and I can't put it off any longer. How did I get here?Our company was off to the races in its first year. We raised seed funding, had a dozen enterprise customers, and needed someone to help us continue to sell. Meanwhile, my cofounder and I would focus on raising our next funding round. We had a very limited runway, and couldn't afford to bring in an expensive sales person. So we hired McCoy.McCoy was the company's first hire, first sales person, and our friend. While a bit unpolished as a sales person, McCoy was willing to work at a lower salary. We agreed that once the company became sustainable, we'd raise his salary to market value. Any experienced business person would at this point widen their eyes at this perfect ingredient list for a disaster recipe. Lucky for me, I had almost no business experience, so I dove into this lake-sized mistake head-first.The working relationship started well. We all worked long hours to do right by our investor (and the company's vision) to make the company a success. By the end of that first year, we had more than doubled our customer base, and tripled our revenue. With this rapid growth, McCoy's personal expectations started to grab hold. We were still young as a company, and not yet sustainable, but it didn't take long for the toxicity to start to set in.McCoy began to start his mornings in the afternoon, and started saying things like "I'm the only reason this company is succeeding." A hard conversation would fix things for a week or two, but eventually the old behavior would return. Then the demands for an increased salary began.McCoy's perspective was that he was carrying the company on his back while we sat back and relaxed. Eventually, every day is punctuated by insulting prospects, insubordination, and watching basketball games to "punish" the company for not appropriately recognizing his contribution to the company. It got to the point where I felt like I was a kindergarten teacher.My perspective, was that thirty customers was nothing relative to the size of the market, and that we needed to grow even faster, or face the harsh reality that our business wouldn't be around in a few months if we didn't. It was something that McCoy didn't know how to process. That's why this impasse was even more my fault than it was his.I was a new manager, unsure of how to give direction, of how to lead, and how to inspire. My expectation was that everyone can be trusted to know what they're accountable for, and get after it, with periodic check-ins.While some thrive in this type of management style (and I have since hired leaders in the company who do), McCoy didn't. It was a huge error on my part to not recognize this difference and adapt how I was communicating our intent. It was about meeting McCoy where he was, rather than expecting him to meet me where I was.I dreaded going into the office for months. I couldn't stand to look across the office at McCoy, knowing he was more likely to be watching a YouTube video than capturing sales, all while the company continued to burn runway.Rather than sitting McCoy down for a true heart-to-heart, the most I could muster was writing "we need to fix this" emails to him. I avoided the hard, but necessary conversation. I closed myself off, making the problem even worse.I felt trapped. McCoy was our only sales person. Letting him go meant there would be zero sales activity until we found a replacement. I tried to convince myself that even if they were doing a terrible job, even five minutes of productivity is better than nothing, right?I knew something fundamental had to change, but was it me, or him? The answer, of course, was both. The experience of managing McCoy taught me the importance of values, and performance, and where they intersect. An employee who is performing, but has values that don't align with the company, is far worse than someone who has strong values, who isn't performing.This is when I learned the most important business lesson I've had in all these years: don't tolerate misalignment on company values. In McCoy's case, both values and performance were off. The decision was clear.Back to the present. I'm about to open the door to the office to tell McCoy that today will be his last day. I walk in. I tell him. The reaction is, as you would expect, toxic. I hear every insult I can imagine, including that I'm a terrible business person. Hey, no argument there.Any doubts I have about letting McCoy go instantly evaporate. In evening, I can't be more more excited about the company's future. I come to work the next day feeling excited, motivated, ready to bring someone new on the team.It takes a month or so, but I find an excellent sales person who helps us double our size over the next two years.As a team grows, there are always challenges with team fit, but I'm so grateful that I got to learn a big lesson early. The symptoms of a value mismatch are subtle, but powerful. They can poison the well if left unchecked. While letting folks go is by far the worst part of running any team, catching it quickly is better for everyone.