In my first graduate education course at Tyler, my professor asked us to think and write about our former art teachers. Many people had positive memories, but my most memorable art teacher was one who frustrated me (while a great teacher, he'd always draw on my paper, which made me really mad- so I'd erase his drawing and do my own). As an art teacher now, I have a sense of pride and perhaps superiority because unlike him, I do not draw on my students' papers. It's a little silly, but it's something I hold myself to.
I guess what I'm trying to say is that even bad experiences, frustration, rivalry can be as valuable as the caring, attention, and encouragement we receive from others. They can drive us to be better, push us to succeed, and prove ourselves. They keep us on the road to success.