Huck comes to stay with the Widow Douglas shortly after the end of the novel The Adventures of Tom Sawyer, and begins The Adventures of Huckleberry Finn with her as well. Huck and Tom find gold in the book, and Huck is now rich! The town suddenly has renewed interest in Huck because of his wealthy status. The Widow takes him in because she is a good person and is truly concerned about Huck. However, she also wants to civilize Huck, or as Huck spells it, "sivilize." She makes Huck go to school each day, learn manners at the table, forbids him to smoke his pipe, and makes him go to church. Another member of the household, Miss Watson, is always on Huck, picking at him for everything he does. Huck thinks the Widow Douglas is a decent woman because she really does have his best interests in mind; however, Miss Watson is a sour old woman who Huck doesn't like very much.
Huck does not want to be "sivilized." He has grown up his whole life an orphan--his mother is dead, and he has an alcoholic father who is never around. When the "sivilizing" gets too intrusive, Huck runs away to the woods where he can be himself.
I think Huck appreciates what the Widow Douglas is trying to do, and on some level, he likes the comfort and ease of life with her. He doesn't have to worry about anything like food or where he will sleep. However, the Widow Douglas's lifestyle is not who Huck is. He would rather be on his own and doing his own thing without any restrictions from the Widow or society.