In rehab we would have these 'polite confrontation' exercises where I would have to tell someone something they do/did that I did not like.
I was terrible at this exercise because when someone did something in real life that I didn't like I would just drink until I forgot about whatever they did, or I would get drunk and unload on them about it.
Either way, I didn't know how to engage in 'confrontation' without alcohol, let alone be polite about it. Most people learn how to do that in their teens. I was learning basic people skills and interpersonal skills in my late 30's.
(No, it doesn't apply to ALL alcoholics, and some alkies suffer the problem worse than others. Just my opinion.)