How not to be a Zebra

My question is different than the "does what university you attend matter?" From the FAQ it seems the consensus is that it generally doesn't as long as the program is accredited with the ABET.

However as a machinist and welder, I've worked with enough engineers to know they are not all created equal. I'm 31 years old and am getting an engineering degree mostly for the sake of engineering. In machining we're always chasing the perfect part, as an engineer I want to design the parts that a machinist is happy to machine, not the ones we talk shit about behind the engineers back.

Which brings me back to my old CO's advice to a new batch of NCOs. He said to us, don't be a Zebra, don't give people a reason to wonder why you have the stripes. I'm wondering what makes the difference between a bad engineer and a great engineer. If all accredited schools pass muster, then are bad engineers just bad students? If schools do matter in the quality of the engineers where do the diminishing returns start on the scale of MIT to community colleges/local universities?