How about:

What brings you to MAC today?
What kinda look are you hoping to achieve?
What kinda colours do you normally wear?
What colours are grabbing your attention?
How do you like your makeup to look?
What kind of skin do you have?
What occasion are you shopping for?
When do you normally wear makeup?
How comfortable are you with bright colours / pinks / applying MU / using creme blushers?
Which colours do you currently have at home?
Why are you considering a new foundation/ what dont you like about your current foundation??

The take-away technique is so hard and sometimes feels totally unnatural but I like your response...

__________________
M A C - a lifestyle...