If you think about it...a song is just really a catchy riff. One where everything is predominately based around it. While you may mute the riff and allow the supporting elements to shine through for a bit...in the end that catchy riff has to come back in to catch everyone's attention and bring it all home at the end.
If you make 3 catchy riffs....what happens is that the listener gets confused and decides that one riff is catchy but the others suck. Which makes his or her's experience a confusing one. You only need to feed them one. Albeit a really good one. Then build around it. Now there are times when you use a secondary riff to support the main riff but that usually occurs at a low volume level. Where the secondary riff is almost implied and not the focus. You always focus around the main riff or as we used to call it in the 'old days' ...the goob.
Again by doing a basic arrangement of copying your 8 bar pattern linearly 30 times or so you can begin to figure out how to start your song, when to bring in the catchy riff, when it becomes monotonous and when to decide to bring in a change in arrangement or a new element to keep things moving.
"you bust your ass to make all the money you can...thinking it solves shit...and then you realize..when and if you get there at all...you got more problems and you missed out on the one thing you can't buy or get back...your life! Spend time with friends and family...You can be broke in other ways too!...."