When there is a special need to signal a divide of sorts (some expanse of or distance in space, for example) that separates
here from
there,
over here will show its presence in getting your thoughts or your bodily self from there to here.
For example, your boorish boss might call you on the phone: "Get your behind over here. I want to talk to you." Here "over" stands for the spacing between your office and his.