Telling somebody to go away. Also said to unimportant people in your life when they try to talk to you. Or how you feel when you feel that you can't move forward.
guy1: Why haven't got a new girl friend
guy2: because I can 't move on
Guy1: she was 5years ago...
guy2: I know
Guy1: Ugh, you love to tread water
"to tread water" is an idiom, that means doing something/being active without making any progress.
That new call of duty game has no real engine or graphics improvements, all the devs did was tread water >.<