I have always prayers with Sunnah but after I came to United States, I saw that many Muslims here (esp Arabic) perform Fard only leaving Sunnah prayer altogether. I know there are two types of Sunnah prayer. One that is stressed Sunnah, the other is not stressed sunnah.
My question is what is the importance of Sunnah Prayer. My concern it, they make the prayer longer, somewhat difficult if they are made compulsory. What are its sources that make it compulsory? Should they be observed or not? Sunni view is welcomed (and any there if there is)?