As soon as someone well-intentioned says something to me, such as praise for having achieved something, or a piece of constructive criticism, I immediately having a desire to prove them wrong, or achieve more than they think I can. I honestly think this kind of motivator is really problematic as a trait, as it just leads to burn-out, and an uncalled for need to prove someone wrong, when feedback isn't something a person should be required to 'prove wrong' in the first place.
I had a conversation with my mom about this a few weeks ago. She was explaining to me that I seemed stressed recently, and maybe should drop one of my extra-curriculars to make things easier on myself. My first reaction? I signed up for bilingual debate provincials right after the conversation. Although this was something I was absolutely excited for, it was initially a reaction to my thinking, and my mom's thinking that I was overwhelmed. I felt a need to prove both of us wrong. Needless to say, I'm very happy I took the risk to sign up for debate as I now love it, but the initial motivator to sign up wasn't out of healthy behavioural patterns.