12. Will and Emma Kiss
Will and Emma's will they won't they relationship had been building up in tension ever since the first episode, even while Will was still married to his now ex-wife Terri- but it is 13 episodes later, in the wonderful first competition episode "Sectionals" from Season 1 that they both finally share a kiss. Will had recently broken up with his wife after she lied about her pregnancy, and Emma's really odd relationship with Ken had also recently ended. Though the kiss was one of the most romantic scenes in Glee's history, their relationship only lasts about another episode after this until they brake up for more than a whole other season. In Season 4 they are currently engaged, but it took a lot of will they won't they to get to this point, and this kiss is what started moving their relationship train forward.