Ideas are not necessarily worthless; it's just that so many people place far too much emphasis on the idea with no consideration for the cost of execution. Unfortunately, the backlash to this flawed assumption has caused the pendulum to swing too far in the other direction, where "ideas are worthless" has become a sort of mantra. The problem with mantras is that they are oft quoted, but rarely contemplated.

Ideas come to nothing without execution, but execution will have no direction without an idea to foster.

The real problems come when someone trades the weight of the idea against contributing work. The extreme of this is an idea guy who "does the hard work" of coming up with the idea, then expects his partner(s) to do everything else while he sits in an armchair sipping a martini.

Execution comes down to playing it smart, and wading up to your armpits in shit. Every founder must have something to contribute on a day-to-day basis to turn the idea into a reality. Every founder needs to do shit work. Every founder is responsible for the product, and must always be looking at it with a critical eye, and discussing any concerns or refinements. Of course, one person needs to be the final decision maker, but everyone shares ultimate responsibility.

Execution and ideas are the chicken and the egg. A bad egg yields a bad product, but failed execution ruins everything it touches.