Tips:

Instead of wrecking the entirety of your cooking when introducing something that may not work so well, put a small amount of the new thing in your mouth with a bit of what you’re cooking.

In this case, take a spoonful of mashed potato without swallowing and then a sip of chocolate milk . Do you want an entire bowl of that?

Sometimes even just smelling one with a taste of the other is enough to decide.

Also, try a big spoonful of sour cream in your homemade mashed potato along with your regular seasonings. Awesome.