Can't Always Be Happy

I want to be happy
But to do this
I must make others sad

I must choose
One or the other
I can't have both

I want to be happy
I really do
This is harder than I thought

I was happy
Last month
Before I knew

But now I do
I can't take back
What has already happened

This isn't a movie
There is no time machine
There are no 3 wishes

So for now
I must think
Until another day
When I must choose