Yes, I was reading about that, that there are more negative emotions than positive. I guess though that it's like dreams and memories; something with "umph" has to happen for it to be memorable; all the bright, sunny, summer days just kind of blend into each other? But have a hurricane show up and you remember it
One thing I try to remember is that most words have two "sides" so whatever connotation you are giving "overwhelmed" you should look for the other side? I would think of surfers :-) and how they'd want a really big, good wave and then they'd ride it but unless it was an "overwhelmingly"

large wave, the ride wouldn't be as good? Or, how about an amusement park ride, a roller coaster? It's fun to be overwhelmed then (just like it's fun to be scared by scary movies). Sometimes being overwhelmed can get our energy back for us? When I'm feeling helpless, I often get really angry which is what gets me out of my helplessness.
I notice synonyms are: amaze, astound, astonish. "I am astonished at how tight that muscle is?" LOL