Ever had a boss or even a teacher who loaded you down with work and just didn't seem to respect you or anything you did? That wasn't fun, was it? Now imagine that the same person actually owns you. You live in his or her house, take orders day and night, and if you disobey those orders, well, good luck. Whatever situation you may have found yourself in with this person was probably pretty frustrating—but it's (hopefully) nothing compared to working for Madam Lockton.
No one in Chains sums up the core of Madam Lockton's character better than Isabel's mother. As Isabel recounts:
Everybody carried a little evil in them, Momma once told me. Madam Lockton had more than her share. The poison had eaten holes through her soul and made room for vermin to nest inside her. (43.19)
Wow—that's harsh. And yet, it's a harshness that Madam well earns. She deliberately raises her offer for the girls to prevent Jenny from buying them, beats Ruth for making noise, treats everyone around her, including her husband, with cold, bitter selfishness, is vocal about her desire for Lady Seymour to kick the bucket, sells Ruth, has Isabel branded… we could go on and on. And on.
But wait just a minute. While Isabel's correct in describing the evil that runs through Madam Lockton, we still have to feel sorry for the position she's in. She's married to a guy with a serious temper, who "likes to be obeyed" (13.14) and isn't afraid to use force to make sure he is.
No, really. When Lockton tells her he's going into hiding after the plot to kill Washington is exposed, he responds to his wife's objections by throwing her against a bookcase and beating her until "Her red eyes perched above dark rings," "a livid, purple welt" (17.40) forms on her face, and she's covered in bruises. Yikes.
While you could argue that Madam brings this treatment on herself just by being, well, herself, we can gather that it's probably a vicious cycle: Madam's selfishness feeds her husband's temper, which creates more conflict, which leads to greater anger and selfishness. We can't justify the way Madam treats pretty much everyone she knows, but being in an abusive relationship with a greedy guy obsessed with politics likely just makes things worse.