I was recently asked by a large company to give a reference for an ex-colleague of mine. This consisted of them asking me to answer 10 questions. Frankly, I'll be surprised if they get much useful information from most such requests, but one question jumped out at me as being a symptom of a bad way of thinking about how teams of people work:
"What kept her/him from being the #1 performer on your team?"
The idea that you can answer such a question is pernicious. It implies that you think of a team as a collection of individuals, working on separately measurable stuff. Indeed, if you can identify a #1 performer on the team, that person probably isn't really working properly as part of the team, and the overall performance of the team would be better if that individual spent more of their efforts helping the rest of the team. It implies that you think of a team as something where the output is the sum of the efforts of the individuals.
I think it's much more helpful to think of a team as a set of individuals whose work is tightly intertwined, and whose behaviour is highly dependent on the needs of others in the team. A good team member is one who performs reasonably well on the individual items they work on, but whose influence on every other team member is to multiply their productivity by some factor. For example, by using their particular knowledge to help others think through problems, avoid pitfalls, and produce better architected and documented code. And, not least, who raises the morale and enthusiasm of the team by making sure that everyone gets a measure of the credit for the team's success.
A team composed of individuals sacrificing some personal productivity in return for improving that of everyone around them is a joy to be a part of, and far more effective than a set of individuals working alone.