Probably it can happen naturally sometimes, but the thing is, when you give them a nice GFE, they APPOINT you to be their friend. They just say: "I want us to be friends. Let's go for a drink, let's go away for a weekend".
Right.
I tell them, friendships just start naturally and not when one person decides that the other will be their friend.
I now get really annoyed when they try to go out of the normal booking format. Maybe some of them are just being nice, but I am so fed up with people trying to approach me outside work.