But back to the original post, I think 'having good taste' and knowing when something feels like the right solution is one of those hard to define qualities that can make the difference between average and great products (and has far reaching effects in any business).
All rational thought depends on its axioms/premises, and there's no rational way to define a new axiom - by definition they are asserted from scratch, so you need to depend on gut feeling to choose a good axiom over a bad one.
Rationalism "only" works to discard or modify some subset of your axioms when you discover that they lead to incompatible conclusions; which is a good outcome if you want to achieve a consistent theory, of course; but it doesn't help in selecting one consistent theory over a competing one. Again, those preferences are led by emotions.