There is a famous story attributed to Korchnoi concerning an Olympiad game. Playing a weak opponent he is soon up a piece. The game progresses and soon he has won another piece. Suddenly he says to his opponent "Do you speak English?" "Yes" says his opponent. "Then why don't you resign?" growls Korchnoi.
While I'm not sure how true the story is, it is always tempting to demand that of an opponent, especially when you are clearly winning. However on some opponents such a comment would be clearly wasted, as they clearly believe that "no one ever won a game by resigning"
One player who this applies to is English IM Michael Basman. David Levy gives a selection of Basman "swindles" in his book "Play Chess Combinations and Sacrifices", swindles that generally kick off long after 'decent' players would have stopped the clocks. However one swindle he declined to publish was a particularly painful loss he had to Basman, where Basman sacrificed a queen in an inferior position. The sac wasn't that helpful, as Levy's advantage actually increased but eventually the succession of short term threats all got to much for Levy who blundered and lost, 18 moves later!
Levy - Basman,Michael J [B03]
Glasgow Glasgow, 1968
1.e4 Nf6 2.e5 Nd5 3.d4 d6 4.c4 Nb6 5.f4 Bf5 6.Be3 e6 7.Nc3 g5 8.fxg5 dxe5 9.dxe5 Nc6 10.Nf3 Nb4 11.Nd4 Be7 12.a3 (D)
12. ... Qxd4 13.Bxd4 Nc2+ 14.Kf2 0-0-0 15.Bxb6 axb6 16.Qc1 h6 17.g4 Bh7 18.h4 hxg5 19.h5 Bc5+ 20.Kf3 f5 21.gxf5 Bxf5 22.Rh2 Nd4+ 23.Kg3 Nb3 24.Qe1 Rd4 25.Be2 Rd2 26.Rd1 Rxb2 27.Bf3 Rxh2 28.Kxh2 g4 29.Bg2 Rxh5+ 30.Kg3 Be7 31.Qh1 Rxh1 32.Rxh1 Bxa3 33.Rh8+ Kd7 34.Bxb7 Bb2 35.Bc8+ Ke7 36.Rh1 Bxc3 37.Kf4 Nc5 38.Rd1 Nd3+ 0-1