I, personally, see SO many unruly Boxers with clueless owners... I think a lot of people see the bully face, and they assume that this is a lazy, easy going breed. Plus, they are right up there in the top 10 AKC breeds, because they do have a goofy personality, but they are also a WORKING breed.
There is a lady in my Obedience classes with a 10 month-old intact Boxer, who is incredibly lax and annoying. She always stands right next to me and Fozzie in class. Her Boxer literally stares intensely at Fozzie the entire duration of the class, yanking and making an assortment of noises. When we are practicing stays or recalls, he breaks them multiple times to get up in Fozzie's face in an aggressive manner (and there is a no dogs meeting on leash rule in our classes). It is great practice for Fozzie's obedience, but she clearly has no idea what she's doing, and I have a feeling it will only get worse as he grows up. He is just constantly "on", bouncing off the walls, and she is a little, older/middle-aged quiet lady who doesn't even try to get his focus most of the time. He's a beautiful boy, too, I wish he had an owner who could actually handle him.