I'm 18, my half-sister is 16, my Mom is 35 and my Step dad is 40 here's a little information about each of them.Me: I'm pretty lazy,  I sit in my room all day when my Mom asks me to do something I do it, the only thing I don't do is tidy my room (Ofcourse I occasionaly do but not often enough) I don't have a social life and I don't do much pretty much your stereotypical teenage boy. Ever since I realised I wasn't helping clean up by doing chores instead I compromised with my mom by cleaning up any mess I made (Which is usually nothing as I'm usually in my room). I always try to make points about having a fair share of the snacks (as we dont get much I dont like it when I come down and there's nothing left for me) so I tried to compromise that way too.My Mom: She was abused as a child, her side of the family is completley broken my Nan turned all (but 1) of my aunts against us and now none of the family wants anything to do with my Mom (I'm pretty sure they'd be ok with me or my sister though). My mom LOVES arguing anything she can get her claws into she will want to argue. My mom lost My dad as he cheated on her, My sisters dad as he tried to kill her and my old stepdad because he cheated on her with her best friend (Who happens to live 10 doors away from us) which cause trouble alot. Things like my sister becoming physically immobile and frothing at the mouth after hanging out with my moms ex-best friend grandaughter after a few drinks (and it's a state she hasn't been in before) it was quite scary and my mom came into that house drunk kicking and screaming for her daughter when it was unneccessary and made an already sad moment worst. Another of example of my mom causing trouble is my sister was being laughed at by my moms ex's family across the road, she told my now-stepdad to go over and have a word (which was unneccessary again) and this ended up with someone with a gun strapped to their waist punching my stepdad's tooth out and breaking his nose, which resulted in me and my sister having to be out of the house for a week. She's also extremely selfish like buying herself 4 bottles of wine over two days, and buying 1-2 bottles of coke for everyone to share and thinking its fair when its like a 50p for us £5 for her and we often argue over not having drinks (I know that may seem silly but all these selfish acts add up) another example is her taking extra food upstairs for my stepdad and herself or an extra bottle of coke and rarely will she ever treat me or my sister.Stepdad: Ex-prisoner, smokes weed, doesn't bring much income but pays for the electric and food. He has cheated on every woman he's been with my Mom has lied to me about what he's been in prison for and I still don't know what. I have reason to believe but no proof that he's cheated on my mom currently and she believes so too (as he's always adding "Hot" girls on facebook) and randomly dissappearing. My mom and him always argue, my mom usually finds a reason to be angry at him, has a drink to calm her self down, but usually ends up with her being violent towards my stepdad he hasnt hit her back but I worry that he will one day and they end up kissing and making up at the end of it (Ofcourse after telling eachother that the kids "hate" eachother, we have told them things we dislike about either of them to both of them but never hate, pretty much somethings you see here we have told them as we have no one else to speak too about it).Sister: I love her to bits, we've been close as we only have eachother as close family and my mom is either working or with my stepdad. She can lie or be a bit weird to get her own way sometimes but other than that she's fine. We both constantly talk about our parents (mostly mom) and we've told our mom how we don't like the guy she's with but she still doesn't listenIf you've made it this far thank you and I appologise if things are a bit out of order but there's A LOT to say and i'm trying to write this in one go. So back to the point about me and my sister telling my mom we dont like the step dad. We did this before with our ex-stepdad caught him taking substances, money randomly dissappeared when he was around he could never afford anything and even after we told our mom (for nearly 5 years) that this guy wasn't worth it she didn't listen to us, and it took him cheating with her best friend to split up with us. Now you have the new step-dad who I wouldnt consider a stepdad, filled with empty promises too look good infront of my Mom (e.g. i'll take you on the motorbike son we can have some fun - 1 year ago said but never happened) and i've done no activities with him. So since he's joined the house; He's an ex-prisoner and i've been lied to and still not told why he's been in prison, a guy has came to our door with a gun and put us all in danger annnnd my mom is becoming drunk and violent and giving him more than me or my sister, we tell my mom this, again doesn't listen.Another thing about my mom is she's never wrong, my sister and mom argued today about them disliking eachother they were both tipsy, my mom comes into my room "You and your sister hate me, your sister just told me", randomly out of nowhere then she changes it too "Your sister told me you think im selfish", and then too "I never said you said anything about you" changed her story three times, the argument keeps going, no one gets any where. She does NOT listen no matter what, and will take anything to offense. I seriously don't know what to do I can't keep up with this lifestyle of constant change it's not fair on me or my sister having selfish, childish parents. What do i do.