Question: Nature is one of our greatest teachers. We often see things that are not so perfect, but we've learned to accept and respect them, and yes, I believe we are here to learn and to tolerate. My question: Is it okay to have sex merely for pleasure? Logically, the sexual organs are there for reproduction but over the years people have learned how to make it an entertainment. How does the teaching of Islam address this? Should we abstain from abuse and respect more the creative function?

Answer: 
First of all you need to know that according to islam, we are made to get attracted to opposite sex and have sex with each other, so that the human race can continue. 
So imagine, if there is no pleasure,then why would anyone have sex? ofcourse no one will. So Allah has made us in this way that we naturally enjoy sex a lot, and as a result, human race continues.

Islam does not discourage us from having sex, but it only regulates that how,when and with whom you can do it without any limits (ofourse with certain exceptions). Islam says that you have to have sex only with your wife only, and enjoy as much as you can. the wisdom behind this point is that islam is made to make the system of society strong. So if man has sex with anyone JUST for enjoyment, then there wont be any single family, but Chaos. Imagine one man makes multiple women pregnant, and does not care about taking care of of mother and child, so who will take of them? no one. they are left alone like garbage and mother alone has to take care of all the responsibilities. So in islam, it is job of man to keep the FAMILY unit strong. keep the marriage healthy and keep his sexual relationship to only his wife, to no one else.
Also, if he merely has sex for enjoyment,then in case a woman gets emotional attached to him, (as she is not his wife) she cannot claim or force him to love her back and take care of her. 

Hope i answer the question.
Islam actually encourages marrying someone quickly if you want to have sex with them. There is kind of a taboo in the Western world to marry without much thought, yet little taboo to having casual sex. Islam encourages taking responsibility for the results of having sex.

The negative effects of sex isn't just about procreation. It is very intimate and brings a lot of social attachment. You don't just have sex with someone and leave them; people make a big deal about losing their virginity because it changes their mentality forever.

Yes, you can have sex for fun, but only with a spouse. Show them respect by marrying them. Islam allows polygamy for those who choose that path, but if you don't like the idea of polygamy, just don't do it.

Once you get married, you are encouraged to have as much fun with your spouse as you can.