One of my biggest, most consistent problems in photography is I'm so mentally focused on the subject, I fail to "see" what's going on in the background of the picture.
Like the car in the OPs' shot above, it's a distraction. Although the car was easily cropped out, I think there's some loss of the "feeling" of the picture with the toy cropped out as well.
Recently, I failed to notice various sconce-style wall lights at my ex step-daughters wedding and reception and it not only threw off the exposure, but white balance as well.
While I can typically crop away background clutter in my pix, sometimes, there's too little left in terms of both "mood" and pixels to have a result I like. Then it's off to the bit-bucket for the picture (deleted).
Obviously, I have a long way to go to take more time to "see" everything in the frame -before- I press the button. But then, with live-action, a shot missed is gone forever.