shaq made it personal to stomp the admiral when he saw him because david refused to sign an autograph for shaq when he was a youngster.. read that in his book.
For the record, that story was totally made up by Shaq. I forgot the details but when Shaq gave details, the timeline didn't match up, and Shaq later admitted it was a joke the whole time when he was called out on it. So if you believe that story, you may as well believe the Chupacabra...