What specific traits or habits do people close to you recognize that would reveal an impostor trying to mimic you?

Nice try evil doppelgänger, nice try.

If I suddenly became a competent adult, I think it might tip people off.

What specific traits or habits do people close to you recognize that would reveal an impostor trying to mimic you?

They ask me what specific things would reveal themselves when they mimic me. Thats probably a red flag.

Well, I shoot myself in the head a lot. It's a habit I'm trying to -- whoops! There I go again.

This is like one of those impossible "wife" questions with no good answer and no clean escape.

"Hey honey, if a clone of me ever replaced me, you'd be able to tell the difference right."

"Of course dear"

"Well how"

"Umm, how about XYZ"

"What if they copied XYZ too"

"ZYX?"

"ZYX! Is that what you think of me!!"

Don't answer this you fools!

Nice try, shapeshifting doppelganger. I already have one evil twin, thanks.

I am unable to speak using contractions.

If I ate something in silence, my partner would likely notice something was off immediately. The sound of even my own chewing (mouth closed, ofc) triggers my misophonia

Personally, I never have my radio on in the car and I near-always back into parking slots.

I joke sometimes that if I had an evil clone you could find out which one of us it was by looking at our left arms; mine is slightly crooked because of a childhood injury

Nice try AI.

• The way I pronounce the word "sorry" as well as my inflection whenever I'm speaking. Only my close friends whom I speak to in private know what my voice sounds like.
• There are words I've made up that I jokingly use around friends. An impostor would not know about this as I speak to my friends privately and I never join chat servers, where bad actors could be eavesdropping. A wrong answer or "I don't know" would out them as an impostor.
• My art. I will deliberately make "mistakes" in my art that are subtle enough to not be seen by most people, but I will be able to tell if someone is trying to copy it. Map makers do something similar.
• Other random details only my friends know about that'd immediately out an impostor once asked.

I make people answer Newlywed Game type questions with me, designate secret meeting spots and places to look for secret messages from me, and make up elaborate backstories just in case.

ETA- despite years of training for this, my husband's answer was - An imposter would be able to wink with just one eye and finish a meal without spilling anything.

Well this obviously depends on how well informed my impostor is. But I would say my choice of sushi or breakfast would be among things that could out the doppelganger. Also my choice of drinks, the drink would probably out the doppelganger faster than the food.

Following your example, I never throw on a playlist or let my streaming app generate one. Albums all the way.

My Kiwi accent (despite not being in New Zealand), my abnormally dark irises, my teeth (nothing particularly unusual except a few have an odd shape), my honeymoon rhinitis, my distinct snoring when I sleep, my semi-snorty laugh, my uncanny ability to quote my favorite media, my asexuality (supposing someone were to try to tempt me in ways that would tempt anyone else), my talent in cryptography (or rather certain kinds), my art style, and how I elaborately express myself all come to mind.