I'm often asked by clients, co-workers and students what's the most important question for a marketer to ask. The answer I always give: why would somebody care? I've found it essential over the years for three key reasons:
First, it forces you to think deeply about what value you're creating for customers. After all, a brand has to be useful to customers in some way, to earn the right to be in their lives. Asking would rather than should is key here. I find should only tends to surface your own assumptions about why customers ought to care, while would encourages you to view what's being offered through the eyes of the customer.
Second, by using care instead of want, it takes you beyond the rational benefit to consider the emotional benefit to customers. After all, emotions largely drive decision-making, so a brand needs to satisfy an emotional need.
Third, somebody rather than anybody forces you to be precise about the kind of person who is likely to care. After all, there are many different rational and emotional benefits that customers can seek, and no one brand can satisfy them all.
Of course, there are many secondary questions to be asked. But if you can't provide a compelling answer to why would somebody care? in the first place, then these are better focused on what needs to be changed...