ST. PETERSBURG, Fla. (UPI) -- A random act of kindness at a Tampa-area Starbucks set into motion a chain of giving that lasted for nearly 400 customers.

Around 7 a.m. a woman ordering from the coffee house's drive-through paid for her own drink and said she'd like to pay for the customer behind her. Moved by the stranger's generosity, that customer returned the favor for the next, who did the same.

The chain grew so big that employees began keeping a tally of consecutive customers who chose to "pay it forward." The tally was over 250 by 1:30.

"It makes your day better, I think," 17-year-old iced coffee recipient Lexie Kane told the Tampa Bay Times.

"It's nice just to do a random act of kindness for someone you don't know," agreed Tim Burnside. The 19-year-old chai tea drinker was so enamored by the fast food karma he returned to check its progress and order a second tea.

As the afternoon rush hour came and more and more customers kept the streak going, the baristas entertained hopes of it continuing until closing and perhaps using a gift card to extend it to the following day.

But around 6:00 p.m., customer number 379 crushed their hopes of a fairy-tale ending. An unknown woman driving a white Jeep Commander refused to pay for anything but her own drink -- even though it had already been paid for. Starbucks employee Vu Nguyen explained the special circumstances but the woman was unmoved and, in Nguyen's opinion, visibly unable to understand the concept of paying it forward.

Copyright 2014 by United Press International