Well I can tell you because it's what I do for a job!
As the pharmacist you are responsible for everything that goes on in the shop from an assistant selling nurofen to the prescriptions dispensed. If anything goes wrong it is your fault.
If the Dr writes the wrong medicine or dose & you don't pick it up its your fault, not theirs!
At any one time I could be: supervising up to 8 staff members, waiting on hold for a GP to confirm a dosage, have someone waiting in the consult room for a wound dressing or BP measurement, checking/packing a Webster pack, and dispensing numerous prescriptions. Also talking to old mrs jones who has about 30 prescriptions & is confused about her new medications.
As a pp said, lots of people drop in scripts, then go do shopping so you can't see them in the shop.
In saying that, I think it's not very good service that you weren't told the wait time. Perhaps they didn't realise you were waiting?