According to a new Harris Poll online survey, younger adults - ages 18 to 34 - often leave tips less than 15 percent when dining out! Yet, when it come to splurging, Millennials are willing to shell out an average $213 for a gourmet meal. Why are Millennials such big spenders on food but cheap skates when it comes to tipping? 

"They're simply not aware of the norms that most older adults are aware of," according to Tony Fouladpour, a spokesman for Michelin Maps and Guides. "Let's just say, they lack the experience."

Others are blaming the poor economy and hardships in finding gainful employment, that makes Millennials about twice as likely as adults 35 and up to be lousy tippers.