I love my parents
Loving your parents is a great thing.
I just feel so lucky to have parents who are so gentle and nice
It is good that you love your parents, and that they are so caring to you.  I am glad that you recognize and appreciate all that they have done.
Yeah, but sometimes they make me really angry and I want to tell them off. My sister makes me angry sometimes too. She puts me through such a rough time.
It's still great that you love your parents, despite being angry with them sometimes. Whatever issues you are facing with them and others can be resolved by showing understanding and compassion.