The meaning of this phrase??

Question

I asked "do all people have the right to be happy?"

and the guy answered

"All people have the right to be happy, but not at the expense of others. In other words, your rights end where mine begin"

but I can't understand what it means.

especially

"In other words, your rights end where mine begin"

what does it mean??

　

Answer 1

at t the expense of: A detriment or sacrifice

Answer 2

That simply means your right cannot conflict with mine, or your rights should not make my rights unattainable.

Example:  I have a right to have a huge, loud party with a live band.  That's what makes me happy.  But you have a right to go to bed early and get a good night's sleep before an important  exam or a job interview.  That's what makes you happy.

See?  My rights end where yours begin.