My doctor is too busy to wait for my phone call. If I don't pick up when he calls I can make a new appointment in 6 weeks. Our tax authorities also work strictly on a 'don't call us, we call you'-basis. It's really annoying. I only pick up calls from blocked numbers when I expect a call like this.
Ha! But you see, that would be way too simple. The way you interact with your doctor in America goes something like this.
Step 0: you obtain medical insurance based on a variety of factors that are too complicated to get into, but let's just say it requires mucho mucho comparison shopping
Step 1: you find the doctor you want to see. Because of consolidation, that doctor probably works at one of the larger groups in your city, which may have 2 or 3 of those
Step 2: you call said large group, to ensure they will take your insurance. If they don't, go back to step 1. If they do, they either are able to book you an appointment on the spot, or need to transfer you to the actual clinic where that doctor works.
Step 3: Arrive at clinic for appointment. Talk to receptionist who will make you fill some forms explaining your problems and some medical history. They will also check your insurance.
Step 4: a physician's assistant calls you in and does a bunch of largely useless vitals meant to catch really really sick patients who somehow stumbled into an appointment for something completely unrelated. You are asked whether you fell recently, and they'll take your blood pressure
Step 5: the doctor comes in, and asks you what's going on, more or less verifying the info you've been giving all the previous people you've talked to so far
Step 7: you go back to this clinic reception's to coordinate the doctor's orders. If drugs, there's a whole new flowchart for pharmacies. If you need additional tests, go back to step 2.
For every doctor, there are 3-5 people in support mode their lives on the phone tracking people down, all in the name of efficiency.