eff both of you, I was rolling.
To appreciate this meme you must understand that double rainbow is retarded. A double rainbow is a relatively normal phenomenon and rainbows frequently appear to be close. The search for a "deeper meaning" is ridiculous when what you are studying is an everyday event, even if that event might not happen to you every day.
So, double rainbow guy was freaking out over what is basically a normal event. It has been speculated that this was drug induced, but put that aside for now. The humor comes from taking the "double rainbow template" and superimposing it over other things which at first seem odd (a sandwhich with meat for bread?) but in reality are nothing to get worked up about (KFC).
It's hilarious, the only thing that is lame is having to spoon feed comedy to you...
Here comes the airplane into the hangar, BRRRRRRRRRRROOOOOOOOOOOOOM!