Understanding how your own mind works as a designer can be crucial to producing better creative results, but getting a measure of your own psychology is only half the battle. Then you have to get into the minds of your clients!
Concept design is a minefield. Especially when the brief is on the loose side. Trying to second guess what your client will go for is a bit like Eurovision. You’ve just no idea what’ll be liked and what won’t, or for what reason.
Logic tells you that they’ll pick the best option available, but what you consider the best might not appeal to them. Then there’s the uncontrollable variables such as what mood they’re in, or how many people they’ve spoken to. You just don’t know how the ball will bounce.
Ultimately, the client wants what they want, and there’s no science to understanding what that will be. All you can do as a designer is give the best set of options you can, believe in them and if possible, steer the client towards what (in your professional judgement) would be the best option. Then cross your fingers!