I'm an introvert,too. Although I'd love to be better at street photography, I have a hard time approaching strangers out in public. The odd thing is, in my job as a videographer, I have to approach and shoot strangers all the time...and have no problem with it. It's like I give myself permission to do it because it's my job. I thought I was alone in being like this until I had a conversation with a couple of other people recently who are the same way...introverted by nature, but able to be more outgoing at work because "it's their job". For me, still photography is a lot like meditation. I have to focus intensely...and not just with my camera. So, to go out with other photographers or to carry on a conversation while I'm shooting totally breaks the spell. Regarding the relationship between photographers and their choice of subjects...the first time I ever really thought about this was at a workshop years ago where the instructor was doing individual portfolio reviews and would bring us in 4 or 5 folks at a time. This meant we were able to hear what he was saying to some of the other workshop participants. There was one lady who was pretty cocky about her photography. When we were deciding what order to go in, she leaned back in a chair, put her hands behind her head, and said, "You guys might want to go on ahead. I'm pretty sure he's going to want to take some time with me." I don't know if the instructor heard her or not, but it sure seemed like he set out to make an example of her. She had decent pictures, but nothing really tremendous. Shots of old tractors covered in weeds, abandoned houses, general landscapes, etc... The instructor asked her why there were no people in her pictures. He said, "You've mentioned having a family. Where are your children and husband? Do you not relate well to your kids? Are you having problems in your marriage and that's why you have no pictures of your husband?" He totally grilled her about the isolation and lack of humanity in her photos until she burst into tears, scooped up her stuff, and ran out of the room. When it came time for my review, the instructor looked over my sheets of slides and asked, "Why are there no people in your pictures? Where is your family?" I thought, "Uh oh...here it comes". I explained that I don't really like taking people pics and while I do shoot my family, I do it mostly just to record family events. I said, "If you'll notice, the vast majority of my shots are taken at sunrise. It's not that I'm trying to keep people out of my shots. There's simply nobody else up and around at that hour except me." He shrugged and said, "Oh, okay" and went on to give me a very helpful review of my work.
Before that experience, I had never really been aware of what my choice of subjects said about me.