Easy to Please
Some clients can be difficult. Their expectations and wants are on the edge of exceeding your abilities, or even reality. No matter how many revisions and changes, the product is not good enough.
On the other end of the spectrum, there are those who love everything you make them and rarely ask for a change. When you have a client that is easy to please, there's this temptation to not try as hard. They'll be happy with whatever you put together, so save your energy for the demanding clients.
Instead, try to go the extra mile for those "easy" clients. They'll show extreme gratitude, and hopefully become recurring clients. Sometimes they can't pay as much, and their needs aren't lofty, but push yourself for them as much, if not more than you would with the difficult ones.
It's like being a musician. Whether you are playing for an untrained ear, or for the connoisseur, the one who knows the difference between Baroque and Classical, play your best. The art will speak for itself, even if there is no one to recognize its beauty.