A thought experiment: you're held prisoner. On the other side of safety glass are five innocent babies. In front of you is a contract to sign over your immortal soul to Satan, a quill pen and a sample of your own blood. You are told that for every five minutes you do not sign this contract, five children will be killed. If you wait it out, they are shot and new babies brought in. What do you do?
Most any atheist will find the choice a simple one, because both the immortal soul and Satan are fictional concepts, whereas the babies are very real. So you swiftly sign the contract and hope your captors hold up their end of the deal.
As a believer? Well, the babies are innocent, so their souls should go right to heaven, right? Whereas you, too, is innocent, a victim of circumstance; everything should be all right in the afterlife as long as you hold fast and don't sign that contract. If the believer eventually does sign the contract, it will not be because of their faith, but because of their basic humanity, a thing shared by most humans: a baseline reluctance to see people slaughtered in front of your eyes when there's something, anything, you can do about it.
Far-fetched? Not quite. This is the memeified, some-guy-in-a-pub version of the basic criticism levelled at believing there's a reward in the afterlife: namely, that this belief has a very nasty potential to reduce the value of life in this world towards worthlessness. This applies to any belief that postulates an afterlife of rewards, heavens and the like.
Believers tend to behave as if this implication doesn't exist, or doesn't apply to them. For good reason: it would be a very uncomfortable thought, if they had to take it seriously. Fortunately for their self-image, their minds are suitably barricaded to block it out completely.
Case in point: [1]