My mother-in-law has never liked me. Now she lives with us (or really, I suppose, we live with her). This is because she cannot live alone. The house is in her name but I pay all the bills. Yet, all I hear is how great her other son-in-law (my wife's sister's husband) is. I can do nothing right and he does no wrong.
It is hard to know I (and my wife, of course) am there when she needs me - going to the hospital, picking up prescriptions, picking her up when she falls, going to doctor appointments, etc. and get no credit for it. I know this is selfish but darn it - I work hard and deserve to be appreciated once in a while.