I learned this one looking at mathematics graduate students. There's plenty for non-geniuses to do, but someone who wants to be exceptional at their work should

I learned this one looking at mathematics graduate students. There's plenty for non-geniuses to do, but someone who wants to be exceptional at their work should almost certainly pick a different field. There's a ridiculous amount of brainpower in the field, and if you're not near the top you're never going to be one of the superstars.