Is it the particular things they have worked on at other jobs, i.e. their experience, or is it the way they talk about what they want to build?
I'd be really interested to hear how I can make myself sound like more of a product programmer.
Describe past work in terms of what was made, not tech used to make it. Relegate tech buzzwards to a minimal "skills" section of your resume.
Use the words "make," "things," and "world" liberally. Say you got into programming to make the things that you wanted to see in the world.
Have examples of things, especially small things, that a non-technical person could use or see.
Have a BFA in some quasi-technological process like stone lithography or ceramics. Describe approaching software with a similar sense of craft.
And the reason why it's important is because startups fail because of bad value propositions, not lack of technical expertise.
Like others have said, the rest is mostly about the way you talk about what drives you. Solving hard problems is nice, but demonstrating that you can think well about building something people want is what you should aim for.