So, my colleague is a really nice person - very friendly, very kind-hearted.
Here's the issue. Sometimes she comes across in a way that is inappropriate, without meaning to. She laughs a nervous, shaky laugh nearly all the time. She laughs in serious situations, in meetings, whenever someone makes eye contact, whenever she trails off in a sentence. And it's not a mirthful kind of laugh, she looks wide-eyed, frozen, even tearful, when she's doing it and you can sense that some people just don't know what to make of it or they think she's strange. It's like some kind of anxious impulse.
I know, from conversations with her, that she experienced abuse when she was a child and has been laughing like this ever since then. But obviously I can't say that to someone who doesn't understand, and I don't really want to bring it up with her because she obviously knows and finds it embarrassing enough. I just wish more people understood and didn't constantly get the wrong end of the stick. If someone brings it up I usually just say "I think it's a nervous thing" and leave it there but people aren't satisfied. I just wish I knew how to help.