Go fish. I don’t have the cards you’re looking for

Don’t tell them who I am:
preconceived ideas–damn it!
I had to deal with those when I got called–oh, so long ago.
You thought I was going to make things better:
give you a mansion by the seaside?
All my talk of mansions isn’t here, you know,
to keep you warm and cozy by the fireside.
Go and save the world, and oh, and by the way,
break your grandmother’s heart
she’ll only see you every 2 years.