From dancing for free coffee to secret apron codes, the world of coffee has some interesting quirks. Let's dive into some lesser-known facts about Starbucks, the ubiquitous coffee giant.

While one Massachusetts cafe is making headlines with its dance-for-coffee promotion, Starbucks recently made waves by reversing its open-bathroom policy, requiring purchases for restroom use. This decision sparked varied reactions online, particularly among Starbucks employees.

But beyond policy changes, there's a lot more to Starbucks than meets the eye. Here are five surprising tidbits about the coffee chain:

1. Beyond Tall, Grande, and Venti: A World of Secret Sizes

While most Starbucks patrons are familiar with the standard sizes, there are lesser-known options. Besides tall, grande, and venti, there's the "demi" (3 ounces, espresso only), the "short" (8 ounces, also known as "kids" size for hot chocolate), and the "trenta" (a whopping 30 ounces, exclusively for iced drinks).

The "trenta" size – 30 fluid ounces – is seen here on the right next to the "tall" on the left. (Joe Raedle/Getty Images)

2. Temperature Tweaks: Your Coffee, Your Way

Did you know you can customize your drink's temperature? From "kids temperature" (130°F) to standard (160°F) and "extra hot" (around 170-180°F), Starbucks allows you to tailor your beverage to your preference.

Starbucks can adjust the temperature of its hot drinks. (iStock)

3. Apron Colors: Decoding the Dress Code

Starbucks' green aprons are iconic, but other apron colors hold special meanings. Black aprons signify coffee mastery, tan aprons denote Reserve and Roastery employees, red aprons herald the holiday season, and aprons with embroidered American flags honor veterans and military spouses. Those with a mortarboard celebrate college graduates from the Starbucks College Achievement Plan, while ASL fingerspelling adorns aprons at "Signing Stores."

While the standard Starbucks uniform includes a green apron, other colors of aprons carry special meaning. (iStock)

Most Starbucks employees, whom the company calls "partners," wear a green apron. (iStock)

4. CIA Starbucks: Where Names are Classified

At the Starbucks inside CIA headquarters, anonymity is the order of the day. No names are written on cups, ensuring officers can enjoy their caffeine fix "incognito." This unique location, reportedly one of the busiest in the country, offers a standard Starbucks menu and a comfortable seating area for unclassified conversations.

A Starbucks is located inside CIA headquarters in Langley, Virginia. (Reuters)

5. The Siren's Secret: It's Not a Mermaid

Contrary to popular belief, the Starbucks logo doesn't depict a mermaid, but a two-tailed siren from folklore. This nautical figure was chosen for its connection to Seattle's port city status and coffee's journey across the water. The siren also pays homage to "Moby Dick," the book that inspired the chain's name.

The creature in the Starbucks logo is a siren, not a mermaid. (iStock)