(I'm glad that, instead of doing homework, I spent my spare time teaching myself more interesting subjects.)
"You were so smart, far smarter than me, but you refused to apply yourself. You wouldn't do the assignments, didn't pay any attention in class, and generally didn't care about school at all. I hated you for that and I'm sorry."
What makes me very sad, as a slightly tangential note, my university had covered grades first semester freshman year. This let me do terribly, learn from that experience, and not have it impact my future prospects. They've since removed that, and I honestly feel sorry for new generations of students to have one less helpful safety net. With a good support system in place to help recovery, the chance to fail (in a scenario that would be "non-terminal") has been critical to my learning to suck less across the board.
Because I knew grades didn't matter and that college was covered I didn't do the work, not because I was lazy, but because it was busy work & I had better things to do like running a regional BBS, cracking software, and writing demos in 6502 assembler.
Someone who isn't interested in school might be willing to work very hard at improving in a sport, or work very hard on their extracurricular club, or work very hard to teach themselves assembly and programming, or to learn a musical instrument. They might even be willing to work hard to teach themselves math, but be uninterested in putting effort into math class.
I guess it depends on if you consider "laziness" a universal character quality or not.