For me it was the 10th Doctor Regenration into 11th. I mean I didn't even notice tears rolling down my face. I ain't a very emotional person but these intense hurt type feelings I have got them twice for Movie/Tv series
1.10th Doctor's I don't want to go!!!!
2. Marley's Death in Marley & Me
So for me 10th Doctors departure was the most saddest plus in the 50th Anniversary special the 10th Doctor again says those words which made it even more hurtful ; (