A famous fashion brand once made a commercial talking about its philosophy. It goes like this: their creations have to be simple, useful, beautiful, dependable, and durable.
To be simple is to have no more components or features than is necessary. To be useful is to serve the purpose that it was created for. To be beautiful is to balance simplicity with functionality. To be dependable is to function as intended. To be durable is to function as intended over time.
These are not bad concepts to hold at all.