A lot of the expressions start looking really cartoonish when you dial them to 100. Even the default smiles I usually keep dialed down to like 40% because of that.
There's a couple that work really well all the way to 100. The expressions that came with Amira (aka Leah) look really good including on other characters. There's also one called "Bereft" that I use a lot on Crystal when she starts losing, combine it with open-mouth at 30% and she looks utterly devastated. Not sure what set that came with but I suspect it's a core one you might have?