As far as being mean? Seriously?
You asked a question and got an answer, whether you believe it or not my answer was intended to be of help to you.
As someone in a similar situation and who has spent the majority of my life coming to terms with my families interesting outlook on life as well as many years of therapy in order to make sure that I choose different, more productive behaviors, I believe I am in a good position to offer some advice.
Now, if you want to "not" take heed and wish to take my advice as personal attack instead of the helpful advice I offer, that is totally your choice.
Your mother raised her daughter (your sister) and I am sure she is fully aware of her negative personality traits, and I am sure she chooses to love her regardless of her insensitivity.
Like I said earlier, I agree with Ginny.
I think you need to work on yourself and change your reactions to toward your family from a negative to a more positive.
If you are here asking for advice and only want to hear, what you want to hear, but insist on putting out negative energy and expecting to get positive energy back.....I don't know what to say.
We are here to help support you, but we must also be true to ourselves and with you. If that means telling you something you don't want to hear then so be it, it is for your own betterment and well being.
I hope you can take this post better and more productively then the last.
Love and light!