What is the most thing which turns customers on / off?

1. Overselling the product features
2. Bad displays and pricing
3. Incomplete answers to queries

Behavior of sales staff.

just say to him you have spicial offer 

Sincere Customer Service and the way on how we make them feel that they are special to us.

There are manythings that makes cutomers turn on/ off 

1) Crowding - there are many research on particular issue, many researches had suggested that perceived human crowding will negetively influence the store satisfaction. 

2) Other store atmospheric cues such as product display , light , music , window dressing etc 

3 ) Employee attitude and behaviour towards consumers 

4) Pricing 

5 ) delivery waiting time 

And there are many more. 

what turns a customer on are opportunities your product or service offers.

what turns a customer off is low value,if your product or service is of low or no value to the customer he/she will be turned off and declines to buy.

a customer will always ask before buying "whats in it for me",what am i gaining,customers need value for their money.

if you can create value you will succeed.

Advertising 

For Commodities: Availability of Product

For Luxury: Importance and Attention to the Customer

I believe the one thing that is a turn off to customers is a lack of graciousness, or ETHICS. A big SMILE is always welcome and makes everything worthwhile. 

From my work history there are2 as below :

1) Customer Off / Feeling he / she is being neglecated after sales.

2) Customer On / Feeling he / she is the heart of your company , meaning not only sale but follow after sale.