Just when it looked as if it was safe to believe that the Celtics have cured what ailed them, they throw up an effortless stinker. In their Sunday-evening, nationally-televised loss to the equally-old San Antonio Spurs, the Celtics proved only one thing: There is still more work to be done, both on and off the court.If the Celtics want their fans to take their championship talk seriously, they will simply have to do better than Sunday’s lackluster performance. Nobody minds an occasional letdown; it is the Celtics’ continued inability to perform in the spotlight against the NBA’s elite that has fans reluctant to get emotionally attached to this edition of the Green.The good news is simple. Paul Pierce and Kevin Garnett appear to have both their health as well as their confidence back. The bad news is, something appears to remain missing from the Celtics, something that they had when they called themselves NBA champions. Since taking over the Celtics, GM Danny Ainge has made a series of moves that have unquestionably made the C’s a dramatically better basketball team. With that being said, Ainge has also not shied away from bringing in players of “questionable” character. From Ricky Davis and Gary Payton to Stephon Marbury and Rasheed Wallace, the Celtics have become a destination point for some of the NBA’s most notorious malcontents. While on their 2008 playoff run, the Celtics received tremendous contributions from both Leon Powe and P.J. Brown, both of whom represented all that was good in that edition of the Celtics. Their contributions went far beyond the front-court bench depth that they provided; both provided the Celtics with supreme character, effort and class.While far from the sole reason for the Celtics’ inconsistent play, Wallace has continued to disappoint, both on and off the court, and the little noticed stunt that he pulled on Sunday was the last straw. This writer has given Wallace the benefit of the doubt for the final time. Following a nasty collision with Manu Ginobili, Pierce found himself on the floor and holding his shoulder in obvious pain. With their season on the line, every one of Pierce’s teammates made their way onto the floor to check on their captain. The only Celtic to remain on the bench was Wallace, all alone, a man on an island.Now more than ever, it is going to take an entire team effort for the Celtics to accomplish big things this spring, and from what this writer has seen, the Celtics are a better team with Wallace on the bench. By himself.