At some point someone is going to ask you to make something cool. When that happens ask them what ‘cool’ means then watch them mumble and say things like, “You know...cool. Like (fill in the name of a product/band/book/designer/illustrator/etc).”
It’s a ridiculously broad term that actually defies meaning unless you know the audience and in whose voice you should be judging cool. It means different things to different people. What is cool to a gun nut might be very different from what is cool to an 8-year old girl. But you can get more nuanced: What is cool to a gun nut might be different from what is cool to someone into cars. Until you know the audience you won’t understand the term.
And it’s not just ‘cool’. Words like cool, weird, sexy, dark, vintage, etc all need deeper explanation. Flag vague language and get specific.