T-G-I-F vs S-H-I-T

A business man got on an elevator.

When he entered, there was a blonde already inside who
greeted him with a bright, "T-G-I-F."

He smiled at her and replied, "S-H-I-T."

She looked puzzled and repeated, "T-G-I-F," more
slowly.

He again answered, "S-H-I-T."

The blonde was trying to keep it friendly, so she smiled
her biggest smile, and said as sweetly as possibly,
"T-G-I-F."

The man smiled back to her and once again,
"S-H-I-T."

The exasperated blonde finally decided to explain.
"T-G-I-F" means "Thank Goodness Its Friday." Get it, duuhhh?"

The man answered, "S-H-I-T means "Sorry, Honey, Its Thursday -- duuhhh!"