Aman, Paradise for Elves, Hell for Men

[Orofacion of the Vanyar]

How could the Valar teach to men that death was a gift to them, if Men would age and wither, while the Valar and Eldar would endure in age and joy. How can that be explained? How can men not be jealous of that?

Many people I know, when given the question "If given the choice, would you want to be immortal?" and the response was the same all around, "No". Why? Because over time, people come to realize that life would get tedious, and death would be welcomed eventually. The elves grew weary of life, this is known. That is why death was a gift in the first place. The elves would teach this to men, and under the proper influence, they would realize this, if not from then, then on their own.

The main reason why Numenor fell was Sauron's influence. If someone keeps whispering in your ear that something is wrong, then you will begin to think so yourself. If Aman would stay clean of evil, then men would not have this little voice saying, "You are suffering, revolt!" and thus, they would become wiser to their gift.

It's all about your environment and experiences. MHO