We do not wish to die; therefore we are afraid of death. We do not like to change, because we are eternal. That is the reason. The background is because we are eternal, therefore we do not wish to change. We want to build . . . the scientists are trying to live forever. They say that, "By science we shall make everyone living for good." But that is not possible. If you want to live for good, in blissful life and full of knowledge, then you have to transfer yourself from this material world to the spiritual world. There it is worth it. There your natural life, mad-dhāma gatvā punar janma na vidyate. The Bhagavad-gītā says: "Anyone who comes to Me, he does not come back again on this material world." Duḥkhālayam aśāśvatam (BG 8.15): this material world is full of miseries and also temporary.
Even if you accept all life style, "Let me live here for good, even it is miserable," that will also not be allowed. That will also not be allowed—temporary, duḥkhālayam aśāśvatam (BG 8.15). Aśāśvatam means "temporary." For a few years you can live, either in this planet or that planet.
So these are the problems. So we should not be irresponsible. But in this age people are very irresponsible. Prāyeṇālpāyuṣaḥ, short-living; mandāḥ. Mandāḥ, means "slow"; he does not understand that, "I have got a responsibility. I must quickly finish that responsibility before the death comes. Before the next death comes I must prepare myself in such a way that I will not have to come back again to this material world, miserable world." That is your responsibility. But we are callous: "All right, let it become what it is." Mandāḥ sumanda-matayo (SB 1.1.10).