If there is a shoe that is nearly ubiquitous on campus, it’s the flip-flop. Bright and flashy, sturdy and comfortable, flip-flops come in all shapes, sizes, colors and prices. From a $3.99 pair at Walgreen’s to a $19,840 diamond-and-gold pair sold by Brazilian jewelry company H. Stern, the possibilities are endless.

Spanning in popularity across the country, and even across the globe, they have become the world’s most popular footwear, according to the San Francisco-based marketing research company Trendscape.

Why the craze? They are the ultimate comfort shoes.

“Flip-flops require minimal effort,” said Katie Rasor, a senior. “They are also great for me because I’m tall. I’m not going to put on cute little heels and tower over everyone when I head out to party.”

Many Stanford girls said they prefered to wear flip-flops to heels when heading out for the night.

“You can actually dance in them,” said senior Chloe Rothstein. “My former roommate once made me wear high-heeled shoes that were really cute. When I wore them to a frat party though, I had to leave after 45 minutes because it was too painful. I prefer to stick to flip-flops.”

Rasor, who owns 10 pairs of flip-flops, has been wearing them for years. Others only discovered flip-flops after spending some time in California, where surf-inspired fashion has spread from the beaches to the pavement.

“The shoes are definitely part of the surfer look,” said Anjail Floyd-Pruitt, Class of 2004. “If a guy is wearing board shorts and flip-flops - that’s a very hot look.”

Guys don’t have to say “dude” and tote a surfboard to join the trend: Men currently make up a quarter of flip-flop sales and have become equal devotees.

“I didn’t start wearing flip-flops until sophomore year,” said Gautam Raghavan, Class of 2004. “But then I got a pair of Reefs — they were the most popular type at the time — and now find myself wearing flip-flops all of the time.”

Raghavan, who is from Seattle, said that most of the people in his hometown did not wear flip-flops. Now that he has graduated and headed outside of the Golden State, he’s having a hard time switching back to real shoes.

“I spent some time in Washington D.C. and people definitely asked me why I wasn’t wearing real shoes,” Raghavan said.

Floyd-Pruitt said she found flip-flops to be considerably less prevalent outside of California, although the trend was slowly spreading, much to her dismay.

Some doctors and health experts are concerned about the rising popularity of flip-flops. Flip-flops are troublesome for a variety of reasons, most notably because of their lack of arch support. For some, walking around for a long around of time with flip-flops can lead to inflammation of a connective tissue running along the bottom of the foot, a condition known as plantar fasciitis.

“It is certainly possible — and biologically plausible — that a lack of arch support might aggravate the condition,” said Rachelle Buchbinder, an associate prof. of clinical epidemiology at Monash University in Australia, in an e-mail. Buchbinder has written extensively on plantar fasciitis and is researching the factors that lead to the condition.

People who wake up with a dull pain in their heel or in their arch are advised to minimize their use of flip-flops — or at least to alternate them with other shoes that support the arch.

Additionally, in order to keep flip-flops on your feet, you grip your toes every time you take a step, causing the knees to lock and the tissue along the shin to tighten-up. Overuse of any muscle, including the muscle groups that allow you to wear the shoes, can lead to cramps or inflammation.

Finally, there is the issue of breaking them in - and the blisters are never pretty.

“I’ve seen girls walking around with bloody feet,” said Floyd-Pruitt. “It looks very painful.”

Despite the pain, it appears that once people catch the trend, they are hard-pressed to give up their favorite shoes.

“I never wear anything else,” said Rasor. “How could I? It would be too much of a hassle.”