Faulting Thinking - the Need to Consider All candidate Moves

Often a move that attacks a pawn, or encourages exchanges is the first one that comes to mind. In the following game - Black needed to consider all candidate moves and not go for the most straightforward one.

Tang, Edward    --    Jiganchine, Roman
Keres mem 39th   2014.05.19     1/2-1/2     D27

 Black to move.

30. ... Bd5

( 30. ... Bc6! -/+ left black with all advantages of his position )

31. Bxd5 Rxd5 32. Nb3 e5 33. dxe5 Nxe5 34. f4 Nc4 35. Ra1 Rd3 36. Nc5 Rxa3 37. Rxa3 Nxa3 38. Nxa6 Nc4 39. Nc7 Nxa5 1/2-1/2