Rafa's bagel on Fed was way more impressive.
In what way? In that 3rd set, Roger didn't even try very hard. He knew he already lost, and so did Nadal.
It's even less impressive than Fed's bagel on Rafa in Hamburg - even though Rafa was tired in that match.
No it wasn't. Fed's 2006 Wimbledon bagel wasn't just incredible tennis, it was a huge psychological victory against a guy he'd been looking as though he couldn't beat, who was now threatening to take away the title that meant most. Nadal's 2008 F.O. bagel was incredible tennis, but it was scored after being 2 sets up & coasting to victory against a player he owned on that surface. There's actually no comparison.
Precisely. Also, bagels on clay are easier to score than bagels anywhere else; serve is the least effective there (unless you are dr. Ivo), so with a clear advantage in rallies, you can expect a bagel every now and then. This is highlighted by the fact that Nadal often wins sets like 6-2 whilst playing 'mediocre' by the words of Nadal fans themselves. And I would agree; on clay, cheap points are rarer than on other surfaces, every game is contested, and Nadal doesn't make any difference between games where he serves and those where he receives: he wants to take them all. (Often doing just that, in fact).