Is it normal to avoid apartment building neighbours?

If you don't want to be chatty, nothing wrong with that. But learn to be more self-confident so you can just smile, say hello and keep walking without worrying about it so much. It does sound stress-full to listen at the door and try to 'sneak out' when no one is there! I'm not a chatty person either but I don't really care if everyone is out in the street, I'll just wave and carry on. It isn't a good thing when you're avoiding them so much it interferes with your freedom of movement, I think you're over-reacting after your previous experience, going too far in the other direction.