Nobody likes excluding people. However, when you are manning a stall at an exhibition or trade show you will not be able to spend the same amount of time with everyone. You might deal with hundreds of people in a single day, many of whom will want a significant amount of your time.
You might want to be as customer-pleasing as possible and give everyone as much of your time as they want. However, this approach could lead to you losing custom as people looking to talk to you get bored of waiting around and leave your stall. Unfortunately, you need to learn which customers are worth talking to and which you should avoid.
This sounds harsh, but it is necessary. For example, you are probably going to come across a lot of people at any exhibition who will end up wasting a lot of your time. They might be curious about your business but have no intention of purchasing your products or services, or they could just be looking for a friendly chat.
If you have time to talk to these people, then do so. However, there will be plenty of people at the exhibition who have a good chance of making a purchase. You need to prioritise these people rather than spending half an hour talking to someone who will never contact your business again.
Of course, there are some people it is worth spending time with. A lot of people will be very interested in your products or services, but might need some persuading to actually make a purchase. These individuals are definitely worth your time.
You should also dedicate good portions of your day to people who will be good business contacts. You should always make time for networking, so people who are not going to buy any of your products are still worth talking to.
After a while, you will begin to recognise what makes a customer worth spending a lot of time with and which people you should avoid. Unfortunately, your time at an exhibition is a bit of a valuable resource, and it can easily fly by without you realising. As such, you must be careful who it is spent with.