I wouldn't say it's the worst, but I agree that stuttering is a serious disability. I have a rare eye condition and have lost most of my vision. Being blind is incredibly hard. It makes doing nearly everything way more difficult (or impossible -- like driving). Having to use a cane was extremely embarrassing to me at first and I'm still a little self conscious about it. But still, when I compare myself to my dad, who grew up with a severe stutter, I honestly think he had it worse in many ways. He endured a ton of ridicule (mostly from his family, sadly), and he grew up afraid to speak and avoided speaking as much as he could; he was incredibly isolated and lonely. He didn't have friends, he didn't ask out girls, he was afraid to speak in class, he only pursued jobs that didn't require much speaking, and he struggled with a massive amount of shame and self consciousness. I have a great social circle and always have. I didn't have a lot of trouble expressing interest in girls and finding a wife. I struggle to do many things because of my vision loss, but I don't at all suffer from all that internalized fear and shame and those feelings of worthlessness and inferiority like he did. Humans are made to socialize and communicate, and when communication is difficult or embarrassing the isolation can have a profoundly negative affect on a person's mental health and self image. The inability to freely and easily communicate is not a small thing. My father's entire life has been shaped by his stutter. He eventually found a wife (though he never expected to), and has had an amazing career and done a lot of important work and been recognized and respected, but that shame and shyness has never gone away. So yeah, despite having what most people would acknowledge to be a serious disability, I would never minimize how bad stuttering is, or disagree with those who say stuttering is a genuine disability.