Depends on the day but MS on any given day tends to P me off. Most frustrating to me are the simple things, like not being able to get my bleeping fingers to work properly when trying to pick up or hold something. Getting up from a sitting position not realizing I can't feel one of my legs - priceless. The numerous aches and pains, sucky fatigue, etc. I could go on and on but you get the picture. And yes, believe it or not, most days I try to maintain a positive outlook in spite of it all.
Oh, and I'm thinking that perhaps Sally's got my house bugged or something - if I'm having a really bad day, you'd lose count.