It's not even that he is hitting his stride offensive, both from distance and because he's figuring out that he's really good at going to the basket and taking advantage of his leaping ability. Nor is it his relentless defense on the wing that replicates much of what we missed when Tony Allen left.
I really loved this article about him in the Herald:
http://news.bostonherald.com/sports/basketball/celtics/view/20220322pietrus_talks_up_celtics_veteran_speaks_out_in_new_locker_room/He's a leadership presence who just loves playing basketball, and most importantly for the Celtics.
I moved to Paris, and then I got drafted by the Warriors (the No. 11 overall pick by Golden State in 2003). I heard about Paul Pierce. I fell in love with that green jersey, but I could never say that because I could never disrespect my team like that. I told myself I wanted to play for the Celtics one day. I never told anybody that, but that’s how I felt. To be honest, I just love the Celtics. I just love this franchise. To play with KG and play with coach, it’s a blessing and I don’t take it for granted. I would love to be a Celtic for many years.
Maybe he's just talking this up because he is on the team now, but I have seen nothing but unbridled joy and energy from him, both on and off the basketball court. He's not going to demand a big contract and he's just a great guy to have around.