When you work with somebody you have chemistry with, it's easy and it's fun. You hardly call it work.
It doesn't matter whether you can or cannot achieve high temperature superconductivity or fuel cells, they will always be on the list because if you could achieve them they would be extremely valuable.
By a great man, however, we mean a man who, because of his spiritual gifts, his character, and other qualities, deserves to be called great and who as a result earns the power to influence others.