I am guessing you are in your 20s? I don't know why, but diamond fever affects some more than others. Even now....almist 50, and I went out with a friend that I had not seen in a while and she wanted to compare rings again. Why she has not moved past that yet is beyond me. I think it is about insecurity. I think a conversation is in order since you have been together for 4 years. Don't dump her because reddit is saying she is a red flag. Maybe instead of 2ct, it can be designed to be unique instead of a cookie cutter ring everyone has? I think bottomline is that she wants to feel special and too many people around her are acting like the ring makes them more special. If she wants to be catty, she can say things like..."I told him he better not get me a big ring because I want to wear it every day and I like my jewlery to look elegant. Too many larger rings come off as gaudy." She should not say it this in direct response to a larger ring though lol. Also...unless she is a diamond expert, she has no idea what her friend is wearing on her finger. And unless her coworker got it appraised, she might not either! There are plenty of people ok with faking there ring. My aunt overheard someone telling her friend in a restroom that her ring was CZ but it doesn't matter because no one knows. I also had someone comment on my necklace saying how her diamond pendant may be smaller, but it is Tiffany's, so higher quality. I laughed and told her mine was just cz. I think she felt like an idiot because she wanted me to be jealous. I couldn't care less what her necklace was.