What is the difference between the following two sentences?
Die Meiers bleiben sehr gern unter sich.
Die Meiers bleiben überhaupt sehr gern unter sich.
I know that both mean something like
The Meiers [very much] like to keep to themselves.
I just can't figure out what the überhaupt contributes here. In other words, why/how would the second German sentence above fall short? Why would the speaker feel compelled to insert the überhaupt?