From pizza delivered to a cancer stricken child to coffee purchased in advance for strangers to acts that transform entire communities, the concept of “paying it forward” has taken hold – and experts say it brings pleasure to all sides.

The phrase, popularized by a book and movie of the same name starring Kevin Spacey, refers to the act of doing good deeds – without expecting anything in return – in the hopes that it will make a difference in others’ lives.

Recent acts of kindness that made headlines include a Reddit user who went on the social media site to pass the word about a cancer patient’s pleas for pizza – and almost immediately, two-year-old Hazel Hammersley had 20 pies delivered to her hospital room.

When an unknown woman at a doughnut shop – appropriately named Heav’nly Donuts – in Amesbury, Mass. paid for another customer’s order, it spurred a heartfelt chain reaction, prompting 55 others to “pay it forward.”

Although it varies, a random act of kindness has the potential to help many people in need and bring a smile to others’ faces.  To put it simply, doing nice things is empowering, says Debbie Tenzer, author of “Do One Nice Thing.”

“These days a lot of people feel powerless. We’re worried about the economy, crime, terrorism, even the weather,” Tenzer told FoxNews.com in an email.  “We can't fix the world's big problems, but we can still fix some small ones.”

This feeling of empowerment can be said to go both ways – as was the case with Hazel Hammersley.

After being diagnosed with stage 3 neuroblastoma in April, Hazel had endured long hospital stays.  In an effort to pass the time, the Hammersley family put a sign up in the window with medical tape reading: "SEND PIZZA RM 4112," Lauren Hammersley, Hazel’s mother, wrote on her blog.

Swiftly, Hazel got her wish.  By evening, over 20 pizzas had been delivered and she even hosted a pizza party for the other patients on the floor.  Family members and nurses were uplifted, noted Lauren.

“We never imagined something like this would happen!  We have been so humbled by the outpouring of support from the online community, because not only have pizzas been delivered, but we have had many donations made to Hazel's Fund from around the world,” Lauren told FoxNews.com in an email.

According to Tenzer, experts say that people are wired to feel pleasure when they’re generous.  When a person does nice things for strangers, even without any possibility of reciprocating, it feels good.  When multiple people do it together, it feels even better.

“The impact and enjoyment are magnified. Even if we’re not together physically, we can still share an emotional bond,” she explained.

Not only are people doing random acts of kindness, but companies – large and small – are trying to promote the idea of doing so.  Earlier this year, Starbucks U.K. began to offer the option of ordering a “suspended” coffee, referring to the Italian practice of paying for drinks that can later be claimed by the less fortunate.

Inspired by the suspended coffee practice, Starbucks decided to work with Oasis, a charity organization.  When a customer buys a suspended coffee, Starbucks provides the coffee to Oasis, which then distributes it through community hubs across the UK.

This helps to provide warmth and comfort for those looking for food or a hot cup of coffee,” a company spokesperson told FoxNews.com.

The company did not have any data on how many suspended coffees had been sold in the UK since the initiative began early spring.  Starbucks does not have an official policy regarding suspended coffees in the United States.

Smaller businesses are also focusing on ways to help their local community.  In Portland, Ore., BeastFit Nation gym is free for members.  All you have to do is promise owner Sergio Jones to do three random acts of kindness.

When he started BeastFit Nation, Jones wanted to challenge the norm in the gym industry and strengthen the bonds amongst people within the city of Portland.

“Shifting the membership obligation away from the dollar and towards volunteering and paying it forward was something nobody else was doing and we have seen from just  18 months that it has the ability to transform communities,” Jones told FoxNews.com in an email.

Members are encouraged to pay it forward in any way they can.  Whether it be volunteering at a children’s hospital, donating to a charity, or even buying groceries for the person behind them, every act – no matter how small – counts.

“We've seen a serious rise in altruism throughout the community and look forward to the kind of continual growth that might not show up on a spreadsheet but makes a serious impact in the lives of all involved,” he told FoxNews.com.

Jones hopes to expand the BeastFit model to other cities and countries around the world.  In fact, members in Tucson, Seattle and Eugene have started their own gyms.  In addition, members have started a PayItForward campaign where they hope to make a documentary about doing 50 random acts of kindness in each state.

Whether big or small, local or international, one cannot deny the fact that people can make a difference for others.  Although it may not seem like it sometimes, random acts of kindness are always appreciated.

“To the donors, I just want to say how thankful we are,” Lauren Hammersley told FoxNews.com.  “This is a memory that our family will cherish forever.”