A is a special snowflake, though for all the wrong reasons. You see, he was born with a special ability that allowed him to see premonitions of his and his loved ones' future in the form of still images. Of course, future here isn't immutable, and premonitions change as new information comes in.
While the ability is incredibly powerful, watching artistic renditions of his many possible deaths took a toll on A's mental health, making him reclusive, and neurotic. He became obsessed with fate and thinks it's out to get him "because his ability upsets the natural order". A could rarely ever tell others about his ability as it could change the premonition in unexpected ways. From the outsiders' perspective, he sometimes just gets the Thousand-yard stare and begins screaming, only to calm down later and refuse to tell why he freaked out.
Though it's not his fault, I'm still afraid the reader would get tired of A's antics, regardless that they can actually see his premonitions. Saying 'Poor A, he unwittingly pushes everyone away from himself" without ever seeing him do that is disingenuous and is considered poor writing. I don't want to change how his charcter is, only how it's presented.
This can be an issue with other characters where their behavior is rather annoying in-universe but you don't want it to be too annoying in the actual book.
How can I ensure that characters like A don't get tiring in the long run?