Does it make sense?
An architect is essentially an advisor on matters of design. In this role of advisor you always have to ask yourself one basic question: Does it make sense?
This pertains not only to the architecture you are designing, but also to the object being created. Let me give you an example. You can design an amazing skyscraper with a sound foundation and a smart layout, but if the client wants to build it in a little village instead of a large city, you have to ask if the need for the skyscraper itself makes any sense.
Of course this is a simple example, but the point is clear. It’s better to question the ideas of your client, than to make a good architecture that is useless. In the end your client will thank you for it, because it always leads to better value for money.