Does it matter if a good employee doesn't get along with the rest of the staff?

First off, what does "good" mean? Does this imply that others on the team are "bad"? I will assume that the "good employee" is a Top Performer, but either way, as the manager I would certainly address this immediately to find the cause(s) of the issue. Dissension can be a short or long term issue, and can actually be a springboard for a leader when handled correctly. If the employee is disrespectful of others, not a team player, unethical, etc and the case can be supported by facts, I'm using progressive discipline to address their behaviors to ensure they are addressed immediately and ongoing. Depending on the gravity of the situation, this is typically in writing with specific expectations and follow up dates.

Yes. Research says that superstars are only useful if they are 10 times more productive than the rest of the team. That means that a good employee who doesn't get along with others is probably hurting the company more than helping it.

It depends. But as long as there is respect for each other, it is ok. If the work environment is toxic, that is not good at all.

Yes it matters in some time because human interaction is essential

As long as it doesn’t effect anyone’s working ability and the results expected of them, then absolutely not. I never went to work to make friends. You’re there to do a job.

Yes, it will show and employee morale will drop.

Yes. In some ways it poisons 'the well' of the company & the people that are "happy employees" "1 bad apple' is all it takes...

No, as long as as the job gets done effectively, this should not even be a problem.

Yes it will affect everyone employees and management sooner or later. I think the saying is oil in water

Yes it matters. You want to keep the ship from rocking. It doesn't matter if one guy is a star if the rest of the team gives up on him, you have the LA Lakers.