Is my dog bad? I'm not sorry.

This is a question we throw out at our house all the time, with the standard answer of "yes, he's a very bad dog". But today it's more of a real question, not just a statement. We woke up this morning to a very cold house. Sometime last night the furnace decided to quit working. The beauty of living in a rental is that all I have to do is call the landlord. So I called our landlady at 9am. At 10am the repair person was already pulling into our driveway in his big orange and white van. Wow that's what I call service! But as Apollo gave his usual greeting (pulling on his leash and growling/barking) the man steps back and says "I don't want to get bit by a dog today!" I quickly assure him that my dog is actually nice, just a good guard dog. But later as the man goes back out of our house to get some tools from his truck, Apollo jumps off the couch and goes up to the man, barking, and pinning him in front of the TV. The man is obviously frightened and says "Get your dog away from me!". I do get up and take Apollo by the collar, but also ask the man if it's OK for Apollo to just smell his hand, since that will usually get him to relax if he can get to know the visitor in our house. The man reluctantly lets Apollo sniff him for just a moment and then squeezes past us and out the door. He stayed out at his van for a long time... Maybe 10 minutes? I was going to try and make Apollo sit on the couch again while the man went in and out of our house- thinking that it would be a good exercise for Apollo to get used to our visitor. But then I realized that our guest probably didn't really want to be used as such a "guinea pig". It's fine for me to try to get my dog to calm down. But what if the repair man left and decided not to fix our furnace because of my bad dog? Was it fair for me to use him to help train Apollo? As much as I wanted to continue training, I decided to lock Apollo up in the bedroom for the rest of the time it took for the repair person to fix the furnace- which he did in just an hour. As the man left, I told him thank you very much for fixing our furnace so quickly and especially on such short notice. But I did not apologize for my dog scaring him. Maybe I should have... what do you think? I just decided to dwell on the positive, instead of reminding him about the negative. I still feel a little guilty about the way I handled the situation, but I'm not really sorry. I probably should have been more careful not to let Apollo growl or bark at all, and I should have made sure that I was always holding onto his collar when the man walked by. But it doesn't stop me from wishing there were more people who weren't afraid of dogs. Obviously, and more importantly, I'm glad that my own child can learn to understand and react appropriately to dog behavior.