Diversification (in a sense, the opposite of "focus") is an important aspect of strategy. You do not want all of your eggs in one basket. Suppose you spend many months or even several years building a substantial down-line in a particular program, and then the company fails or your account gets canceled because of some unforeseen event. Your income can suddenly disappear!
My enthusiasm is higher when I'm in control of as many different projects as I can handle. Prospecting for new clients, setting appointments, returning phone calls, solving impasses, negotiating price and closing a transaction are the ingredients of a full day! The more I have to take care of, the more in control I feel.
We need to understand that our job as a salesperson has a well-defined ROI (return on investment). Crossing that line, i.e., wasting time with a lost deal, following up on clients with no potential, using mail and personal deliveries instead of fax, e-mail and conference calls, may prove harmful.
As contradictory as it may seem, we need to focus on efficiency, and diversify our opportunities, to accomplish more, without wasting precious time. My personal strategy is to have multiple independent income streams, each one with the potential to grow exponentially, as well as a large number of closings "on the pipe".