Why we cannot eat so much sweet?

My baby sister is eating a sweet now...

Why do we need to go to school?

Q: why do we need to go to school (This is a question for me i.e. Boy)

Boy: ... because we need to learn things.
Dad: what things?
Boy: ... how to behave and how to use technology.
Dad: :-)

Boy: ... because when we grow up we want to buy a home for our family.
dad: profound. But why is that related to school?
Boy: ... because we learn things from school and find good work. Boss will pay us salary and we get money from our bank.
dad: We get money from bank only after we put money in -- as investment.

Boy: when you grow up a girl will say I-Love-You and marry you.

Boy: we need to be smart and knowledgeable!
Boy: we need to learn how to make movies