Help the confused dater complete their thought.

My best friend gave me some terrible dating _____, and now I'm hiding in the bathroom on my blind date.

The correct answer is advice.

"Advice" is an uncountable noun in English. It cannot be pluralized with an "-s" (advices) and cannot be used with the singular article "an" (an advice). To count it, you would have to say "a piece of advice."