What to/not Buy At The Big Box Stores?

[Tariq B.]

Flippers, Contractors, Anyone Really...

What items have you found you should buy at the big box stores and what items you should not and shop at the smaller supply houses?  

Such like vanities, flooring, trims, windows ect etc. 

I have found trim to be better at the smaller places and sometimes lumber 

But drywall, paint and cabinets (depending on the type) cheaper at the big box stores. What’s your experience?