Pitfalls are words that are often used wrongly. Sometimes this is because two words have a different meaning even though they sound the same.
Your friends seem really nice. versus You're (you are) so funny!
That's my new bike, do you like its colour? versus It's (it is) such a lovely day.
Whose water bottle is this? versus Who's (who is) that girl over there?
Their main passion is dancing versus They're (they are) new here. versus There is not much to do here.