I do not use the waiting room for either. The first one - I go in right on time or a minute after and her office door is open and I go in.
The second has a complicated door system in a converted house - so you always have to ring the therapist to come open it - I always go in right on time or a minute late there also.
I despise sitting in a waiting room for anyone and for a therapist, my anxiety would go higher than usual.