It's just easy... and safer... not to get involved.
For as much as she dislikes social interaction, she loves to watch it. She usually has great insight on conflicts simply because she's mastered the art of the wallflower so well that everyone truely forgets she's there. This also has it's disadvantages as people have talked about her not noticing that she was within hearing distance. As well, if she happened to have a solution to a problem, she'd usually be over-looked and ignored. Though it hurts deeply, she's come to accept that she can't change it, she's just unnoticable and forgetable. Usually she bottles up the pain and trys to avoid attracting any new pain. This is why she can usually be found on her laptop in a secluded space; trying to block out the world that she feels has already blocked her out. Her blatter problem only made her distance herself more. If anyone needs to find the bathroom, you can usually look a few feet to the left or right of wherever she happens to be.
Despite all this she does care about others and for people she knows, she'd gladly do whatever she could to help them. However, she doesn't really know many (or maybe any) people.
A shoulder bag, this contains usually a spare pair or two of undies and pants as well as her ever present laptop and headphones. She also has spare glasses on her just to be safe and a box of cookies.
Lisa grew up in a "middle-of-no-where" town on the country-side of Pennsilvania. In school everyone knew everyone, so when she was dubbed as the wetter, her social life was over. Especially since it continued to be an issue later in life. She had simply found it emotionally easer to avoid people than to try to explain. Her grandmother, the only family she has left, enjoyed her nearly constant company. However the old woman knows she won't be around forever and doesn't want her grandaughter to completely cut herself off, she is the one who urges Lisa into the situation she now finds herself in.