His suicidal offense. Watching his daredevil tactics was so much fun (See his match with Orton at RR '08) and he always found ways to give us memorable moments. Plus he was given the top spot on Raw after years and years of Cena and Triple H. Cena was injured, the ratings tanked when HHH got another shot, so someone, anyone different was an incredible breath of fresh air. Just so happened that someone was a longtime fan favorite who was finally given the WWE Title, long after he was due in the eyes of many fans, and the writers weren't incompetent enough yet to have him immediately drop the belt within a week to a "top guy" like they did with Christian.