Wow, I thought I was the only one that did that! My heart always jumps when I get a PM, but I haven't gotten a bad one in ages. I have disabled PMs a few times because of PMs I have got in the past. I'm sorry for anyone who has goten bad PMs as well.
But now if I ever get a bad PM, I approach it with optimisum. That way the sender knows they are not getting to me.