"I don't know why I'm even thinking about my gender identity. I'm fine. I don't even have like ACTUAL issues like the people who are ACTUALLY this identity do. I can't believe I'm even thinking about this when real people with this identity are suffering."
"My gosh, I'm so cringe asking my friends to call me by a different pronoun. I can't believe I'm just like cosplaying this identity in front of everyone as if I have any kind of real claim to it. This is just like when I was a kid and would tell people to call me by other names because I didn't like my birth name (a thing totally unrelated to gender identity for sure), this is so childish why am I doing this."
"Someone just called me by the pronoun I put in my profile, they don't even know I'm faking it. I can't believe I had the gall to get excited about that. I'm so ashamed."
"Why am I wasting the doctor's time talking about gender affirming care? This is such a waste of everyone's time and money when I'm not even really this identity! Other people need this way more than I do, and by pretending like this I'm bumping them down the list!"
"I feel so much better after gender affirming surgery. That doesn't mean I'm like... actually this identity though. I really should stop playing around and pretending like this."
Fun fact: It doesn't go away! If you're thinking like any of the steps on this list, there is no point where suddenly you became a real trans/nonbinary/genderfluid/whatever person and are given an official certificate that proves you're allowed to say "This is my identity." And even if that did happen, you'd be like "ah man I can't believe I faked my way into getting this certificate I don't deserve." The reason is because you're already real and valid, and the only person who can decide your identity is you. There is no committee to accept your formal application to join the secret club.
You can't just wait for the day you become valid. You already are valid, and the only way to stop that voice from saying "ah, but I'm not really" forever is to burst through the wall like the koolaid man and say "THIS IS ME, ACTUALLY! I'M HERE NOW, AND THIS IS ME!"