I think emotions are useful in a lawyer. Being able to understand and empathize with people will make you better at not only reading folks, but being a gosh-darn good and nice lawyer that people will recommend.
Well, it's useful to understand them, but that's not the same as having them. It's like it's a great asset to me in my job to have a wide ranging knowledge of musical tastes and stylings, but it's nothing but a liability to actually have any myself. And nice? What? I'm not hiring a spiritual adviser or tour guide for a month in Tahiti, I'm hiring someone who - if necessary, and even if not - can destroy someone else's life, their family, their dreams, their business and their bank accounts and never give it a second thought.
And I agree with 'empathize', it's 'sympathize' that would be all wrong, as the first is understanding, the second is actually feeling. That I understand (comprehend) why people like a certain kind of music, what they get out of it, what they want it to look like and feel like, what it MEANS to them, has absolutely no bearing on whether I find it good or not, and even less impact on it's meaning to me. Like an actor has to be able to understand & empathize with someone who is deeply humiliated and embarrassed over some failure of modesty or decorum so they can portray that ---- being capable of being humiliated, or personally feeling embarrassment, or having anything even remotely resembling modesty or caring about decorum in the first place are all career ending deals in the acting profession.
A good lawyer - like a good medical doctor, or good university professor for that matter - is in a position where if you are emotionally invested in the outcome you've already lost.
And people recommend lawyers based on their winning cases, not by how nice they are. It's like sports, perfectly encapsulated by the words of the great American philosopher Leo (The Lip) Durocher when asked why he couldn't be a nice guy for a change.
"Nice guys! Look over there. Do you know a nicer guy than Mel Ott? Or any of the other Giants? Why, they're the nicest guys in the world! And where are they? In seventh place! Nice guys! I'm not a nice guy – and I'm in first place." After pacing up and down the visitors' dugout, the Dodger manager waved a hand toward the Giants' dugout and repeated, "The nice guys are all over there, in seventh place."