Look at it this way...

The doc, as described above, has several people to see with a whole heap of legit unavoidable reasons as to why he might be delayed and force your appointment back. I'll not reiterate those reasons.

Patients, on the other hand, have one person to see, at a specific time, an appointment made at the patient's behest to solve the patient's problem. One thing. One job. If said patient cannot be arsed to get to their appointment on time the doc in question has every right to get cranky. That appointment could have gone to someone else who'd have needed it a little more urgently than, for example, someone who can't get himself/her kid out of bed on time.

That doc didn't need to apologise. You were wanting to see him, after all. He's providing a service to you. You've 'bought' a moment of his time. For you to be late for that is extremely disrespectful in the first place. The doc doesn't have time to hold your hand and suck up. He's late, after all, so he needs you in and seen and out ASAP. He's doing the best he can under very stressful circumstances which really should be understood by anyone making a doctor's appointment.

If you/a patient expects to be seen bang on the dot then you/they are severely deluded and extremely entitled. The later in the day an appointment, the more likely it is to be delayed. That's just how it is. If it's a fifteen minute appointment, for example, get there half an hour ahead of time and plan for three hours. Any time you get back is a bonus but never expect any.

While there are legit reasons why a patient might be late most of those reasons are avoidable by getting up and setting off early. You know, like anyone with a shred of common sense would do.

"To get there early is on time and showing up on time is late." Both an old Megadeth lyric and a golden life rule for anyone requesting an appointment with someone. Doctor's appointment, job interview, date, asking a friend for a lift somewhere, whatever. It also works well for court-appointed meetings.