I just wanted to say, in your response to notion that 2008 may have been the most fun one for Nadal fans...it's not just that, though it was very fun. Obviously, with the Wimbledon win, getting to #1 finally, and the OGM. I think it's mainly because of the level he was playing at on clay that year. I'm not saying it was overall his best year, because he won 3 Majors in 2010, and you make a case for 2013. I'm just saying, and I think
@MargaretMcAleer is of a similar opinion and will back me up on this: I don't know if he ever played at such an amazing and consistently amazing level of tennis as he did on the clay that year. I don't even know if that is quantifiable. It's an eye test, and a memory test. I think for those of us who shout out 2008, it's because of that particular run of extraordinary level, on clay, especially.
All of the big 3 have had many great runs of being pretty unbeatable. And they also had ones of being nigh on untouchable, meaning runs of peak performance. That's pretty hard to do, and stands out in memory.
That makes sense - and I trust your knowledge of Rafa's game more than mine, for obvious reasons. I think the one mark on Rafa's 2008 clay season was that weird loss to Juan Carlos Ferrero at Rome. Otherwise he was perfect, winning Roland Garros, Hamburg, Monte-Carlo and Barcelona. But...it is also hard to beat 2010, when he won all four clay big titles (didn't play Barcelona...do you remember why?).
Anyhow, the numbers do reflect some of what you say. If you compare Rafa at Roland Garros in 2008 vs. 2010, he didn't drop a set in either, but in 2008 he recorded 3 bagels and 9 breadsticks. In 2010, none of either. So he was more dominant at RG in 2008 than in 2010. In 2013, he dropped a set in the 1st and 2nd round, to Daniel Brands and Martin Klizan, respectively, then took five sets to beat Novak in the SF, including a 9-7 fifth set. So in terms of dominance, it was 2008 > 2010 > 2013.
Rafa's Clay Seasons: 2008, 2010, 2013
2008: 24-1 matches, 59-4 sets, 6 bagels, 16 breadsticks
2010: 22-0 matches, 51-2 sets, 3 bagels, 6 breadsticks
2013: 39-2 matches, 90-11 sets, 8 bagels, 9 breadsticks
I didn't realize how many more clay matches he played in 2013 - that was due to adding Santiago, Sao Paulo, and Acapulco early on when he was building himself up after injury.
Anyhow, it does seem he was a bit more dominant on clay in 2008, though he still managed a perfect record in 2010 but not the other two years. UTS's Elo says his clay peak was in 2013, though that could have been due to playing more matches.
We shouldn't forget the fact that he won 8 clay titles in 2005, though 5 of those were 250s and 500s. And of course he was so good on clay, that there were many years he did the "trifecta" of Roland Garros and two Masters. 2006 was also undefeated on clay, winning RG, Rome, MC, and Barcelona. 2007 was also great, with a trifecta plus two 500s, but he lost to Roger at Hamburg.
Anyhow, I think Margaret makes a good point: that 2013 was a bit more balance in terms of surfaces with the USO and three hard Masters, but 2008 was probably his clay peak. But it is hard to beat those 7 big titles in 2013, compared to 6 in each of 2008 and 2010.