For me it has to be a toss up between constant visual disturbances which can last months on end and worsen when I try to undertake any sort of physical activity.
Or brain fog, which I find so scary as it really takes away the essence of what it is to be human. You can't read, you can't write, you can't even talk and get your words to come out right. You literally can not even process your own thoughts clearly, and worst of all most people who look at you have no idea how awful and frustrated you are feeling.
"You look alright to me"......they say....