There's an expression of the Nuu-chah-nulth of the Pacific Northwest: "Hishuk'ish tsawalk"—Everything is one. As they say, no-one is an island, and human sociability is all about receiving, interpreting, and reimagining cues from other people. Back in school I was such a military nut that I adopted parade posture without any actual training. They talk about becoming your parents, and come university I noticed I'd picked up a lot of my father's speech patterns without realizing it. Rather than counterfeiting, I consider this a natural process of adaptation and evolution: it's basically expected you'll absorb influences from your environment (language and accents being the most obvious). I've yet to meet anyone whose personality was fully-formed and immutable since childhood.
Dont worry too much about this, I think most people's personalities are made up of, or influenced by the people they admire or spend time with. I can name a few people who I am "ripping off" personlity wise. It's normal, and also easy to criticize yourself for it because you ARE you. No one else can read your thoughts. You are just recognizing who influences you and theres nothing wrong with that :)