It was one business in its own parking lot, the lot was full but easy enough to maneuver around in. I am trying to turn into the business, lady pulls up and blocks the entrance and exit by stopping parallel to it and lets someone out very slowly. After about 10 seconds I let out a light honk and give the "what the fuck" hands. 

The lady that got out then walks around to the other side of the car and starts to help an old lady out. There is now 4 cars waiting to get into the parking lot. 

Once I saw the old lady I felt like an asshole, but on the other hand the car could have easily pulled into the parking lot and gotten even closer to the front door.

AITA for honking?