[Joe 6-pack]

Perhaps the biggest burr under my saddle is the use of ordinal vs. cardinal dates in professional communications/reports. I spend far more time following up on, and clarifying this than perhaps any other recurring issue. I will receive correspondence stating:

"I contacted X, and made an appointment to meet him tomorrow."

The problem is, I and others may not review this note for a day or more after the appointment when, "tomorrow," has become yesterday. It's much more precise to say, "I contacted X, and made an appointment to meet him in person on Monday, August 31, 2015."

[posterchild]

Such ambiguity is a nuisance as well. It’s similar to when people use local terms, abbreviations, or initials and expect everybody has their local knowledge.
OC - Osceola County? Occupied California?, Ontario Canada?
Tri State Area - which 3 states?