Emotional triggers are the worst for me, even worse than physical activity.
Even simple stressed make me weak, like when I have to make a decision or if someone asks me a question that I can't easily answer. I often think people around me think I am faking my weaknes in order to get out of answering or making decisions...which is far from the truth.
I can't handle watching someone do something that might be dangerous, like your example of watching someone climb a ladder, makes my legs weak.
I often think that I don't have any tolerance for stress. Whatever the body does to handle stress doesn't function for me.
I think one of the worst things is if someone asks or expects me to hurry, I try to hurry and then my body fights back and slows me down, sometimes so much that I have to sit or lay down.
Every once in a while, this makes me start wondering if somehow the MG symptoms are all in my head, that I am doing it to myself, especially since the stupid Social security disability doctor suggested that possibility. I know this isn't true but I can't help but wonder.
If I am home alone with no phone calls or interuptions or expectations, I feel almost normal, but as soon as anything happens that causes the least bit of stress, I am back to feeling MG weak.
I hope this helps.
I wish the best for everyone.