Because you can be hardworking and still an idiot...or just not that bright.
As far as not that much imaging, it depends who you are with. My attending knows that I'm going into radiology and he lets me spend a lot of time with ultrasound, which is a modality that I never have (nor will, most likely) been comfortable with. The ultrasound technician is great at showing the anatomy and taking pictures of interesting findings for me. I've also been able to follow patients to IR for fibroids.
"Sadly, there are no integers on this scale, so your gangly adolescent attempt to be clever has proved futile."