If you dye your hair bright blue, you're likely to get some criticism from people who just don't understand your personal style. When you're on the receiving end of criticism, you are being judged in a disapproving way.
The noun criticism is most often used to describe negative commentary about something or someone, but it's just as correct to use criticism to mean "an examination or judgment." Critics who review books and movies consider their reviews to be criticism, whether they're positive or negative. So the criticism you receive doesn't have to be all about your faults; it can actually be a pleasant experience.