why do most people act like they're not real?

this has just been on my mind but every....interaction, per say, that i've had in these past few days has felt like me dealing with a bunch of npcs, everyone is a bit of a redundant side character and i'm not entirely sure how to feel.

i went to the corner shop just down the block, caffeine fuels the mind, i was a bit peckish so i decided to drop down there for a monster and a snack. i grabbed the monster, but they only had the blue. i asked the lady at the front if she had any green ones, and she mumbled something i didn't understand, maybe i clicked the wrong answer or something, but i tried again, and again she just mumbled again, i thought whatever im not gonna deal with this so i just walked out, without paying for the monster. now there's a picture of me up in the store, and im not sure why. when i asked to speak, she clearly didnt wanna speak to me, so why put my picture up?