This guy (http://en.wikipedia.org/wiki/Emanuel_Lasker) was a chess generalist (able to play most position types comfortably), and chess world champion for 27 years. He succeeded by playing moves his opponents found most uncomfortable (murky tactics vs positional players, 'boring positional plays' vs flashy tactical players).

There is some disagreement today on whether Lasker was really about psychology or merely ahead of his time. My opinion is he did use psychology, but he also had very good positional sense which most of his contemporaries did not share... (read more)