They're not the fire department
The number one thing that gets people when they call AAA is they have an idea that AAA is like the fire department. A towing operator waits around at an office, until they call, and the guy jumps in his rig and races to the scene. While they always strive for 30 minutes or less, it's not always possible... and really it's not something that you can get upset over. The trucks must operate within the speed limit, so there is no "racing to the scene".
Second, they must take priority highway calls first as a contractual requirement: so if someone is 45 miles outside of town on the main highway, they get helped before you do in your office or home.
Third, they get a lot of calls. When I worked for AAA in the Arizona Roadside Call Center, we answered in excess of 300 calls per day just in the Phoenix Metro Area alone. It was worse in the winter when our trucks were grounded in Flagstaff as it was too icy to drive on the roads.
So just remember when you call AAA that their drivers are not the fire department, they go from call to call with little or no down time (I actually had to order a driver to take a lunch once!). If you're comfortable in your home or office or in a parking lot, unfortunately it will be 'when they get to you', dangerous situations will always take precedent. Such as a baby locked in a car... we had 7 trucks dispatched at once to one call, and who ever got there first got the call. Luckily we had a AAA-Owned Fleet rig 4 blocks away who stopped changing a womans tire while it was still on the jack. She was ticked off even when she found out why he had to go, leaving the car still jacked up.
Most of the time though you'll wait no more than 20 min to an hour at the most in the Phoenix Area, just don't be upset if it takes a bit longer.