People ultimately have faith in order to get into heaven. Heaven offers eternal life and pleasure. So why not? Imagine eating bowls of your favorite ice cream without worries. As someone who has a sugar intolerance, that sounds wonderful.
But what gives you the most pleasure? For me it is crossing the finish line after struggling to get there. Maybe it's reading a thousand page book (wow, did I really just read that). Or finishing a 5 K (those daily runs paid off). Or going on vacation (after months of saving, working, and planning).
So for me, and I assume most, the best pleasures come after months of delayed gratification. So if that is true, then heaven would be filled with work, sacrifice, and suffering. That's why we invented purgatory and stories of angels trying desperately to save the downtrodden - because we instictively we know it's true that pleasure equals work and heaven has the ultimate pleasure.
Why do we ever get off the couch on earth when we can play video games, watch movies, and eat until we can eat no more? Because that is not the ultimate pleasure. And listening to angels play their harps in heaven for all eternity isn't the culmination of pleasure either.
So I do not want to have a heaven of nothing I have to work for ...