The answer to both questions is dependent on what you are trying to bring in with you!
If what you have is :
A. A legal import, and/or
B. Within your entitlement for tax exempt/duty free.
Then IMO the answers are No, and No.
P.S. As Loren has indicated it is not just "Customs".. there is also the "Qaurrantine" type staff who are concerned about animal and plant diseases and products etc... Coming into Australia (fr'instance) I would suggest that the agricultural inspection might well be more rigorous and stressful for some...