when you find a shirt you really like and wear it a couple times and it starts doing
I hate the thing
It’s called pilling. I noticed it it happens on areas that move a lot/come in contact with other parts of your body (like the sides of your shirt where it can touch your inner arm). You can reduce this by double checking you’re washing according to directions and air drying instead of using the dryer. They also make pill removing devices, but I don’t think they work very well.