Gifts

It being the season that people are giving gifts and treats, I'm wondering how other vegans politely decline non-vegan gifts? I had my first run in with that today, when my boss purchased a package of k-cups (coffee) that had milk in them. My boss and I are close friends and she is very aware of my choice to be vegan. She thought she was just buying me vanilla flavored coffee. Since we're so close, I was able to easily tell her that I couldn't drink it and then leave them out for the rest of the office to enjoy. I'm sure there will be future situations that will be more difficult to navigate, so how do other vegans handle it tactfully?