I am less worried about the needs of the person in front of me reclining than the chances of the morbidly obese person I get next to me and then am told I have

I am less worried about the needs of the person in front of me reclining than the chances of the morbidly obese person I get next to me and then am told I have to keep the armrest up because the other person doesn't fit. Hence, put me next to the emergency exit which on some planes seems to have more room in front too