What are the most common reasons you fire an employee?

We've got a typical turnaround but rarely ever find the need to fire someone. I suspect that's the case for many other IT companies. There are simply so many other options available for developers, and if someone is not happy, they'll gladly just leave.

The longer your career the more you see people's employment being terminated for a variety of reasons.

I'd say the primary reasons I have had to let people go (not in any specific order) are:

1. Repetitive performance issues, and the inability to find them a good home in the company where they would succeed.

2. Poor Attitude or bad team fit.

3. Inability for the person to grow with the organization which typically leads to being a bad team fit as the company grows.

4. Lack of funds

Hopefully "Spending too much time on HN" doesn't make the list.

When he fails the performance review with a bad vote. Probably he doesn't work at an high level or he has some relationship problem that makes difficult for him to work in a good team.

I never fired anyone, but I expect the most common reason would simply be restructuring of an organisation, changing needs of the employer, and not so much anything the employee did.