Sorry about the surprise visit. You might want to work on boundaries with her. For example, let her know that surprise visits are not allowed. You can also have boundaries for topics--we won't talk about religion, etc. That might sound harsh, but it's what I've had to do with my own mom. I also won't engage with her in a conversation about what a victim she is. It's easier for me because I don't live anywhere near my mom. So, my boundaries are on the phone. I also wouldn't go visit her, and wouldn't have her come visit me. You might just have to set some of these boundaries to keep from having to deal with these situations.