Yes some of the so called pros never get over some fears, some have en event in their past to cause this but with others it's a lack of understanding on the subject... people fear what they don't understand.
Nervousness or being overly concerned about something can create tunnel vision causing everything else to go to hell in a handbasket while that one thing is getting all the attention.
Examples... calling out engine failure memory items when we hit wake turbulance or slowing the plane at high flight levels due to turbulance and dangerously approaching stall speed... that's fear crippling the old chap.