How many people do you really see and interact with in a week? If you’re using drive-thru windows and ATM machines, it’s fewer than it could be. By going into the bank (or restaurant, or whatever), you have a chance to smile at a real, live person. You have a chance to be pleasant and to possibly even chat a little while making your transaction. After a while they’ll get to know you. If you’re wearing logo wear advertising your business it’s likely that they’ll eventually talk to you about that. I’ve had several people order or refer other people to me just because I got to know them by going inside.
One more thing—pick an off-peak time to do your business. The teller will be chattier if there isn’t a line.