Goldberg was a careless klutz in the ring. During one match against Bret Hart in WCW, Goldberg carelessly threw his leg up to kick Bret and nailed him hard in the jaw. That ended up giving Bret a (real) concussion and eventually led to the end of Bret's legendary career.
From Bret Hart's wikipedia page...
At Starrcade, Hart defended his WCW World Heavyweight Championship against Goldberg. During the match, Hart was struck with a mule kick to the head, resulting in a severe concussion. Hart later speculated that he may have suffered up to three additional concussions within matches over the course of that day along with the days immediately following Starrcade, having been unaware of the severity of his injuries. As a part of this, Hart placed Goldberg on the post in a figure-four leg lock which ended with Hart hitting his head on the concrete floor. The sum total of those injuries left Hart with post-concussion syndrome, and ultimately forced his retirement from professional wrestling. Hart wrote a Calgary Sun column in which he said that Goldberg "had a tendency to injure everyone he worked with."