The marketing guru Philip Kotler gave us al the P-funk (the PPPP), and a lot more. But most of al he gave structure into the world of marketing. Here is an good article where he also talks about passion:

This guru believes in brand extensions. Especially his own. Thirty years ago, Philip Kotler injected method into the madness of marketing with his seminal textbook, Marketing Management: Analysis, Planning, Implementation & Control. Now 67 years young, the indefatigable iconoclast has kept his brand of seminal thinking as fresh as ever, cannibalising his own concepts of the past to create striking new paradigms for marketers in the 21st Century. India-today.com