Imagine if I had not noticed that the pills were different, and instead of medication for arthritis, I took pills for seizures. What if I had taken them - and they were contraindicated with my other medications. The pharmacy would have been in BIG trouble. However, I realize mistakes can happen and no harm came to me because of their mistake.
Here's the important part:
Whenever you pick up a prescription from a pharmacy, LOOK at it before you leave the premises. If it is a new prescription, speak to the parmacist about it, ask questions. If it is a refill, check to make certain it is the one you are supposed to have. If it looks different, ask about it. You will be safe, plus, you will save yourself some trouble in advance.