Price, quality and reliability.
All three.
It doesn't matter how great a price is if I don't receive the product or it's of poor quality.
Same with, if it's excellent quality, but doesn't get delivered, no one gets to enjoy how great it is, or how economical.
Likewise, if it is delivered when I need it, if the quality is poor or the price has gone up, not good.
Communication: Tell me about new products, but ones that I can use. Don't tell me about PSMO's if I run a burger shop. Tell me when the price is going up, or when you have an opportunity for me to buy long at a great savings.
Save the idle chit-chat until after you have met all of my needs. Interupting yourself to ask if I saw the big game is probably going to lead to mistakes.