People with a disorder tent to says this because they are rrying to program their brain to believe that, mostly try to live a life as normal as possible, it is positive way to think because if not the disorder will take over, is a fight against one self... I also was terrified by the dark, even getting paralized, now I can be in dark place if I know the place (like my home) or if there someone else with me, but before I couldn't handle it, I will cry even if there werw other people inside, it was total panic...
I don't remember the reason I am so afraid of the dark and it really doesn't affect my daily life now, but I had to program my brain to get it in this level... I still feel panic if it is a sudden happening or I'm not feeling well!!!
Just as @agathat says.
On a relateable scale (if you have no disorder), it's like showering then suddenly remembering an embarrassing moment of your life.
Why do Yaoi manga alway be like: “Hi, I’m a person with *insert disorder*, but it doesn’t effect my daily life! *Immediately cue said disorder ABSOLUTELY effecting their daily life!*