I do this all the time. In fact it's unusual for me to follow a thread of conversation for more than about five or ten seconds, uninterrupted. I have really just noticed the extent to which this affects my social life in the last year or so. It really has quite an impact.

I am hard of hearing and I didn't get hearing aids til about a month ago, so that was a big reason, I found. I just couldn't follow conversations, whether in a loud room or a quiet one, so I got into the habit of tuning people out, partially to divert the pain and embarrassment of always feeling left out. Now I have the hearing aids and I still do it. I have to really channel my energy to focus on what's going on right in front of me. I find it very challenging.