What and where is Heaven?
What is heaven? What goes on there? What does it look like? Do you eat, sleep, poop there? Are you aware of your relatives and friends that did NOT make it? What happens on a day to day basis? Will you ever get bored? Where is heaven exactly? "up there"?
Does God allow free will there, can you be sad if you want to? Do babies that die have to spend eternity as babies? How about old people?