This is my 3 main reasons why you should use foreplay, I wish you will found my article helpful for bring you success.

Physical Reason- Most of the guys tends to want to skip over the foreplay level during the sex. Most of the guys want to skip over the foreplay to get straight to sex. For example, if you're a man, and you try to get, after you watch a baseball game, straight to sex, probably you're going to have physical problems. The vagina has erectile tissue (like the men penis) which needs to fill with blood to accommodate penetration. Else penetration will be difficult and uncomfortable for both of the sides. Without foreplay her vagina won't have secreted any natural lubricant, which makes penetration very hard and uncomfortable. Women's likes a lot of talking and softness before the sex, its gets her mind ready as well as her body. Good foreplay will make your sex much better.
Enjoyment Reason- Without foreplay, your sex will be very quickly and boring, probably you don't enjoy at all. If you don't want to act like a sex machine, make some bang-bang and go to sleep, foreplay it's for you.

Sex it's all about fun, so if you don't having fun in your sex, probably it wouldn't be good. Make foreplay for having real fun during the sex.

Passion Reason- Want to save high Passion for sex? Make foreplay before any sex. Because all the fun that coming with the foreplay, you will start to love it more than ever. The foreplay will increase your Passion for sex, so you don't stop making it.