Questions about “impairment”

I have been drinking every single night for well over a year now. I started off kind of slow, maybe a 4-5 mikes hards a night. That only lasted a couple months. I quickly moved up to 1/2 of a fifth of vodka, to a full fifth of vodka, per night. That rate has been steady for almost a whole year.

And yet, i still dont feel impaired. I still feel like im totally in control of my own choices, i dont make stupid decisions, even my motor control isnt really inhibited. I just dont understand how people make out alcohol to be something that makes them stupid and reckless and clumsy

I do feel good when i drink, trust me. Its what helps me sleep every night (melatonin and sleeping techniques dont really help, im a sleep walker and i find it difficult to fall asleep most nights when im sober) but i just dont exhibit the classic signs of being drunk. I dont walk funny, i dont even talk funny or slur my speech when im blackout drunk.