There are two ways of looking at the world:
1] We are here for this world.
2] We are here to prepare for the next world.
The difference between the lifestyle and choices of a person who looks at the world the first way are going to be immensely different than that of a person who looks at life the second way. The difference is not between a person who believes in the next world and one who doesn't. There are plenty of people who believe in the next world who live their lives totally for this world.
Our entire culture is singularly focused on this world - and we all get sucked into that. Some more, some less. But we are all victims.
Mussar Haskel: Beware!