I've been damned lucky. The worst paper, the one were I had to read most of the citations and quite a few of their citations before I got it was http://conferences.sigcomm.org/sigcomm/1997/papers/p011.ps and yes it took over a month before all the pieces settled into the right corners of my mind. Perhaps more accurately, it took months for my mind to create the right corners for the concepts to settle into.
But that was fine - I knew before I started it was the seminal paper on the subject, and so it would be worth whatever effort it took. The idea of wasting that inordinate amount of time going down that path with one dud after another makes me shudder in horror.
The process was utterly a time waste except for when the paper in question was a survey paper.
now you have sixty+ complex papers, at least a third of which are not actually very important, useful or thorough.. and where are those original, carefully chosen ten you started with ?
side note - the "focus on the figures" reading advice does not scale, since most search is first and foremost with text. Which of the now-eighty papers (and growing, the field is hot) are the ones you cared about and understand.. ? "piled higher and deeper - PhD" indeed!