Knowledge is limited.
Imagination encircles the world.
The most important thing to remember is that people can only see the words you type. You are giving them no other clues about yourself - they can't see the expression on your face or hear the tone of your voice, for example. Some people don't care what they look like on IRC, because they think it's a game. Others take it more seriously than they take their real life. If you explore IRC for long enough, you're bound to meet both types of people.