I liked when you said "expected more than they were able to give" because I have felt that way on the giving end. Being a person who battles social anxiety, it's very hard for me to open up even if I want to.

To me, "fair weather friends" are people who are only friends when times are good. To say people are these types of friends because they won't open up is not right. This person may be dying inside to share with you, but being reserved, cautious, etc. may mean they are just afraid of being judged and maybe losing you. I experience those thoughts almost every day!