You get the sloppy message if there were a significant number of inaccuracies or mistakes that caused the eval meter to swing about. You'll get a different message if you maintain a small advantage throughout the game but blunder a mate in 1-2 moves. Definitely not speaking from experience or anything. :.(
"It was sloppy."
Sort:
When reviewing my games I often get this: "You played better than your opponent in the opening, but it was sloppy." I take it that this is a problem or else why mention it? What can I do, then, to "unslop" my playing?