I Am a Proud Grammar Nazi

If the word you are referencing starts with a vowel, you should be using "an". If it starts with a consonant, you would use "a". For example: I had [b]an[/b] awesome weekend." versus, "I had [b]a[/b] bad day."

"He was holding an adorable cat." versus, "I thought it was a really cute puppy!"

Come on, people. Basic english here!