This one was easy. There are many likeable couples but the one that stands out to me is Klaine. (Kurt + Blaine)
How could you not totally ship this couple? Watching their relationship grow in S2 was one of the best parts in the series. Kurt went back to McKinley and shortly after Blaine followed him, not wanting to be apart from him. Their relationship kept on until the beginning of S4 where they unfortunately broke up and didn't get back together for quite a while. But they got their happy ending and got back together eventually. Klaine 4ever!!11
Also, how sweet is it that they met due to Kurt asking a random stranger a random question?
Day 15- The couple you ship the MOST