Wilf almost TOO unselfish?

Over the past few games particularly Zaha seems reluctant to beat the last man and have a pop at goal himself. Today was a prime example. He outmuscled the Hull player ten yards inside the Hull half and started to run in on goal but rather than possibly try and get a shot away or push on into the box he squared it harmlessly to a Hull player who cleared his lines. He seems to do this quite often these days. Is it a confidence thing or riding to instructions do you think?