Stereotyping is a form of prejudice and is also the root of racism and discrimination. A stereotype usually applies to a whole group of people who do something in a certain way. To them, it seems natural, but to some people it's weird. Often, a name is given to the group, and to every individual. For example, nerd is the stereotype name for someone who is usually a computer whizz and can't play sport very well. This however isn't always true, because many people are computer whizzes and also good at sports. But, if you saw someone who you didn't know come to school with disks and computer stuff, you would probably say, "he's a nerd," or "she's a nerd." The problem with that is that you are making a judgement of their personality without actually knowing what they are like. Another real-life example is towards blonde haired people, women in particular. One journalist went for a weekend with blonde hair, rather than her usual brunette look, and noticed that no-one took her ideas seriously.
That's what stereotypes are all about. When society has an exaggerated idea about a group of people, when you see someone who seems to fit the description you judge them as that stereotype.
Some stereotypes are called labels, because it's literally like a label stuck to you. There's no harm in making that point, but labels can also be a name for an individual. For example, if someone was known as Lazy- Bones, it means that they don't always do their part of the job, let the team down, and anything else that can be connected with being lazy. That person now has two choices: one is to actually live out their label and turn into a big lazy person, or they can fight back and prove that they aren't lazy.
Most stereotypes focus on the bad things about someone's personality, or not necessarily bad, but more like an area that they're not strong in. If someone gets labelled for something they can't do, it could have bad psychological effects on