What does impersonal mean?

Impersonal means having to control or conceal your personal feelings. It also refers to the lack of personal warmth. Aliens and robots are said to be impersonal and that is the edge of humans, having that indescribable warmth. Here are the following sentences that use the word impersonal in a sentence.

The boss is very impersonal to his employees.

The impersonal touch of the stranger is alarming.

I thought he had changed but he is still his same old impersonal self.