I mostly book online nowadays and only have to contend with my own patience and the competence of the programmers at the airline who design and write the code for the online booking.

One observation I can share is that you usually get more knowledgeable agents anytime other than the night shift. In the past I often had to hang up and start over with agents working at night. I finally got to where I could tell they were brand new and incompetent, so I would say "thanks," hang up and start over. I once had a male agent book a roundtrip as two one-ways, boy that took a few calls (during the daytime) to get straightened out.