Why do older siblings always hate younger siblings?

Well I wish it wouldn’t have come to this but today was some accident where a poor 17 year old got hit by a train and I told my younger brother today that I am so unlucky that a train had to hit a good kid instead of him, who never brought my family and me nothing but shame.

I’m not proud of what I said, considering the fact I’m 26 and he’s 16 but here’s the issue: even after years of introspection, questioning myself am I wrong for this or that, I simply found out I am in fact not responsible for being vitriolic towards him lately. I have a job, cant move out yet sadly, but want to so bad, so I told my mom “you buy whatever he needs, I will finance my own food etc”. Soon as I buy myself something, he either eats it, drinks it or breaks it (everytime he’s near my PC or PS5 I start trembling)

For even more perspective: we share a room, I cant go anywhere else, so I sleep in the same room as him. What he does is smokes in the room while I’m trying to sleep at 3 am. He failed 7th grade (he’s still in elementary school) and all he does is just trying to be like a hooligan (hes inspired by fights at football/soccer matches etc). Me? I prefer staying out of trouble unless I really have no choice but to defend myself. Now, what makes me hate him is not the fact that he eats all my stuff or drinks all my stuff, breaking my stuff is a very bad line to cross yea but the worst things are the smoking while my girlfriend is visiting instead, blatantly interrupting us while we try to study or watch a movie or he simply just doesnt let me sleep when I have to go to work in the morning (7 AM). Hes disrespectful, rude, egotistical, narcissistic and selfish, he never wants to share but takes all my stuff etc. I never taught him to be that way, I used to love him, babied him, took him to my gym to help him, took him to my breakdancing classes, wanted to do sports with him etc. But he chose bad influence and all my kindness, politeness, refusal to get physically into a fight with him and all my effort to keep my parents happy when I clean our room and take care of our home goes out the window cause he purposely makes a mess, he even puts cigarette butts on my bed and smears stuff on it, leaves a half eaten plate of food on my bed, he does everything to make me mad. So yea, I dont hate my brother cause mom and dad didnt like me more, I could give a crap about that less, I hate him cause I dont get to have peace and quiet at home, I cant relax, I cant study, I cant even have proper time with my gf cause she wants to leave everytime hes in the room making noise on purpose. Yea I need to move out but lowest rent is 450$, and its a studio apartment of like…20m². Cant move out yet so I have to endure. I wish I didnt say those mean words to him but he forced my hand so I wont ever be nice to him again. Im supposed to be mature but his behavior just throws me off and I wish he was 18 so I could whoop his ass finally.

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