What is Overly-friendly?
1.
A person who goes out of their way, or the way of normal humans, to engage in interaction with other humans, or animals, in otherwise non-interaction situations.
An overly-friendly person is:
The security guard at your office that insists on telling you "welcome back" every time you walk in.
The lady who says "hello" to everyone she knows or remotely recognizes. And then says "hey you" to those whose name she doesn't know.
See
