Creed's pride is what cost him the 2nd fight against Rocky.
He was getting hated on for the first fight. He dominated in the 2nd one. However, he was so focused on knocking him out and not doing what he did in round 15 last time (basically not punch back and just get hit cause he was hurt)
"STAY AWAY FROM HIM"
He tried to tell him, but his pride is what led to Rocky knocking him out.
Creed's pride got him again in part 4.
Rocky still should have known he doesnt think clearly when fighting sometimes