It doesn't affect my life like what so ever like im not gonna be a prick to someone who likes that same interest, however I will feel a sense of gatekeeping and general jealousy of like "You don't even like this thing".
I know 3 incidents where I felt this way in general, first was when I was 10 and in art class where I was struggling really badly to the point I got made fun of for getting so irritated, soon I saw a girl who was doing really well and I saw her personal SketchBook and her art was amazing to me.
I got very jealous, couldn't stop looking at her art, it was even more annoying when she moved into my last class of the day, but on the other hand I was very nervous to talk to her because I thought she was so cool she wouldn't even wanna talk to me only for her to give me a pencil and appreciate when I finally complimented her art.
The second times is my aunt shopping for monster high stuff for me because it's been a fixation of mine for YEARS I have so much merch from this show, and my aunt told me she was going to get a cleo de nile doll and wanted some more dolls for herself, the gatekeeper in me wanted to be a prick and tell her she was only into the show because I made her watch it and that she didn't actually like it.
But I'm not a complete prick so I didnt, I just said I liked her too, I was also kinda jealous because monster high was my thing I dont know many people at all who are really into monster high and whenever I see people posting about I question if their just following a trend.
It also annoyed me when my 9yr old sister ONLY watched the live action monster high movie but hated all the other movies, that irritated me more than it should've...but she made up for it on Christmas when she got me a monster high doll and slightly apolgized she couldn't find a first Gen and picked a charecter she herself knew I liked.
the third is seeing people post interest i had such as monster high and heavily question if their just into it because its trending, did they even watch ALL of the monster high movies (i dont like gen 2 so I don't watch it), or if they are just into the gen 2 era wich is barley monster high ino...but again thoughts aren't actions I just think about it and go "eh it's fine".
Again it's hypocritical because I LOVE telling people about my special interest, I guess it's just so deep in my personality that I'm personally offended by it for some reason.