Going through law school, I found consensus on two points:
1. It’s like why people have a proofreader. You’ll miss your own errors even while rereading because the idea already makes total sense in your head, whereas other people need to experience it for the first time. The worst symptom of this is when the self representing lawyer tries to engineer their own happy ending, and nobody is there to tell them they’re gonna have take an L on this or that.
2. Lawyers have to be very assertive and aggressive in court, almost bullying. There is something really quite off-putting about seeing someone personally do that on their own behalf when the other party isn’t. Logically it shouldn’t matter to a jury but it does. And it’s far easier to get flustered and make mistakes when someone is pushing back on YOUR aggression in a person to person conflict.
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