It is nice to be recognized when you walk in to a store, but if multiple employees (some across the room) shout out "˜Hello!!' as soon as the door opens, it can come across more as a "˜duty' rather than "˜we're glad you're here'. This can be compounded by the employee(s) not looking at the person they are greeting.

Remember customers are people too and can tell when you are being friendly and when you are just doing what a manager told you to do.

An honest greeting (even if it is not as a customer first enters) is much more welcome than a dutiful greeting when the door opens.