Here is a good situation which will explain- you have arachnophobia. It’s Halloween, and as is customary, Susan is decorating the office. Some of the decorations include webbing with little plastic spiders and a big rubber spider at the corner of a cube.
Situation #1. You march into HR, and inform them you have arachnophobia, and Susans decorations are making you uncomfortable and they should punish her. They ask you if you ever mentioned this to Susan (or anyone), you say NO, and they mark you down as a idiot troublemaker- you will never get a promotion again, and will be the first to be laid off.
#2. You do mention it to Susan , and she sez “Oh, I am so sorry, I didn’t know!” and takes them down.
#3, as above but Dave the office joker hears this, and fills your cube with spiders, webs and a big rubber one that falls from the ceiling on you. You complain to HR. They fire his stupid ass.
That’s what you do when you have a phobia- you tell others. Then they can help you. People do not want to make you uncomfortable- in general.