Back in the late 1960s, rated in the mid-1600s, I was in one of the chess clubs in Chicago and picked up a book by Peter Griffiths, The Endings in Modern Theory and Practice, took it home and spent a lot of time studying K+P and R+P endings. That was combined with playing over several hundred master games while trying to guess the next move. In my next tournament I defeated four Class A players before losing to a Senior Master in the last round! I ended up with a rating of around 2100 before giving up OTB chess. The miracle of an elementary knowledge of basic endings and pattern recognition! "One of the biggest misconceptions about chess is it requires a lot of memorization. In reality, while some memorization is required, pattern recognition plays a crucial part in chess mastery." - Mrs. Paul Truong (aka Susan Polgar).
I recently played an interesting ending on Instant Chess. The initial position is evaluated at -0.63 by Stockfish 6 which means that black (me) has a slight advantage, but probably not enough o win. I ran 20 Shootouts using Stockfish 6, Komodo 8, Fritz 12 and Gull 3 and all the games were drawn. White was able to save the game despite being a Pawn down because of his centralized pieces, but in the actual game the two passed black Pawns resulted in victory, so white's defense had to be precise...something he was not able to accomplish
White ended up losing for two reasons: 1) he allowed Rooks, a long-range piece, to be exchanged and so was left with a short-stepping N that was unable to cope with black's separated, passed Pawns and 2) he failed use the opportunity to create a valuable asset in the form of an advanced, passed Pawn of his own.