In Chapter 2 of The Watsons Go to Birmingham - 1963, the two things that Kenny thinks are wrong with him are that he is smart, and that he has a lazy eye.
From a very young age, Kenny has been able to read well, and he loves doing it. At first he thinks it is cool that teachers think he is smart because of his reading ability, but he soon notices that while the teachers are
"smiling a mile a minute, all the kids (have) their faces twisted up or (are) looking at (him) like (he is) a six-legged dog."
To make things worse, the teachers are so amazed at his precociousness that they parade Kenny through the school, having him read before the older classes. The other kids resent this treatment of Kenny and give him a hard time, but his brother Byron comes to the rescue. Byron, who is older and super-cool, sticks up for Kenny, and the other kids, seeing this, begin to leave Kenny alone.
The other thing that Kenny thinks is wrong with him is his lazy eye, which causes one of his eyeballs to "rest in the corner of (his) eye next to (his) nose." Kenny tries all kinds of exercises to fix his eye, but nothing helps, and kids often tease him because of his odd appearance. Byron helps Kenny with this problem also; he shows his little brother how to keep his head straight when he is talking to people and look at them sideways, so his eyes are looking in the same direction. Byron's trick works, and Kenny becomes much more comfortable interacting with people when they are not teasing him or staring at his lazy eye.
the 2 things wrong with him are his reading skills and his lazy eye