I was interested to discover from The Observer that Tim Martin named his Wetherspoons pub chain after a teacher who told him he would never make a businessman. Of course we are robbed of the context of the remark by a brief piece of journalism.
Teachers can use lines such as 'You'll never succeed...' but in my experience often follow them up with '...if you carry on the way you are.' It can be the catalyst for change.
Whether you consider you got your results because or despite of your teacher, good teachers don't care. They like it when others win. That's why they are teachers.