Burris Ewell epitomizes everything that's wrong with the most hated family in Maycomb. Lazy, dirty, ignorant, and disrespectful of authority, Burris very much takes after his old man, the odious Bob Ewell, one of the most despised men in town.
Burris turns up to school just once a year to fulfill state education requirements. After that, it's back home to a life of ignorance and squalor. It's all part of a tacit little arrangement between the education authorities and the Ewell clan.
Unfortunately, Scout's new teacher, Miss Caroline doesn't seem to have got the memo. When a louse crawls out of Burris's filthy, unkempt hair, she takes fright and orders Burris to go home and get a bath. But Burris, being a Ewell, is not about to take orders from Miss Caroline—or anyone else, for that matter. He responds by giving her some trash talk before angrily storming out of class, presumably not to return for another year.
When it comes to Burris, it's clear that the apple hasn't fallen far from the tree. He's just like his old man, and one can certainly imagine him growing up to be every bit as much of a lazy, abusive, racist person as Bob Ewell.