I encountered many great songs in 2013 but the 1 that stood out to me the most which's not a single is ...
ARASHI - P・A・R・A・D・O・X
http://www.jpopsuki.tv/video/Arashi-...4ab03b3712f3e0
It's a no brainer on why LOVE is the best selling album of 2013 cos of this song , it's enough just for me to buy it , but of course it helps that they put out some of their best sounding singles in their discography for 2013 too