Saying no to our customers is our biggest selling point. People don't expect it. They have never come across any salesperson that was willing to say no to customers even if it means he/she won't sell anything that day.
Whenever we say no in a sales meeting, the room usually goes silent. A shock moves across the room and people look at each other confused. Then we explain, we tell them why we said no.
In our experience, saying no and having a good explanation for it is better than saying yes.
We say no every day because we want to protect our customers against themselves. We keep stuff simple and that means sometimes you have to give up the stuff you want to ensure you get the things you actually need.