So I want to write a Mac application. Do I write something you readers want or do I write something I want?
Pros–I’m forced to narrow your choices, work with you to clearly define goals, must meet deadlines.
Cons–I’m writing for you and not me, must meet deadlines, I might hate what you want me to do.
Pros–I make me happy and can ship with whatever quality that will make me happy.
Cons–I’ll suffer along and not learn and probably stay within my knowledge boundaries.