在餐馆享受到非常好的服务时，我通常会给餐费20%的小费，要是服务还不错，就给15%，服务不怎么样的情况下给10%。

我以为自己已经够慷慨了。最后却发现我给的小费最多也就算个平均水平。

 
在经济不景气的环境下，给多少消费才合适呢？小费上涨已经有一段时间了。康奈尔大学酒店管理学院(Cornell University School of Hotel Administration)的迈克尔·林恩(Michael Lynn)说，上世纪50年代，人们通常会给帐单金额10%的小费。到了70、80年代，小费标准就涨到了帐单金额的15%。现在，人们通常会给15%到20%的小费，通常的比例为18%左右。

小费为什么会涨？已经就小费写了不下40篇论文的林恩博士说，人们给小费是为了给服务员留下好印象。他说，如果我想让服务员真心喜欢我，给的小费就得高于平均水平，而如果不想招服务员讨厌的话，就得留下平均水平的小费。这样的态势导致了小费的上涨趋势。

小费的总体规模蔚为可观。以色列本-古里安大学(Ben-Gurion University)的阿扎尔(Ofer H. Azar)在美国攻读博士学位时对小费进行了研究，他估计美国人每年给的小费总额约为420亿美元。

虽然现在出现了经济危机，但别指望小费能在近期“缩水”。林恩和阿扎尔认为，社会认同因素还是有可能不断推高小费水平，虽然这个过程会逐步进行。

阿扎尔说，这些变化要经过几十年时间，并非逐年发生。他认为小费的平均水平不会在未来5年内达到25%。

虽然我多方俭省，但事实上我对餐馆服务人员怀有同情之心。我在1980年成为全职记者之前的最后一份工作是在加州的一家法国餐馆打杂。收拾餐桌这份工作十分累人。服务员会分我们一部分小费，对于当时的我来说，周六晚上拿回家的额外15或20美元是很大一笔钱。

当时正值伊朗人质危机期间，而这家餐馆的老板刚好是伊朗人。（听起来有点像彼得·赛勒斯(Peter Sellers)电影里的情节，而当时给人的感觉也的确如此。）就算往好了说，餐馆的生意也只能说是清淡。有一个周日的晚上，餐馆里当班的只有一名服务员和一个杂工（就是我）。不知什么原因，那天晚上生意很好－－客人的桌数远远超出我们能招呼的数量。

当班的那位服务员干这行已经有一段时间了。他告诉我，试图为每位客人提供很好的服务毫无意义。那是不可能的，这样做只会让所有人恼火。相反，他说他会挑选几桌客人精心服务（也会得到丰厚的小费），有余力的时候才会去招呼其他的客人。实际情况也正是这样。

新泽西一家意大利餐馆的女服务员最近也对我和妻子克拉丽莎(Clarissa)来了这一手。我们的晚餐过了很长时间才端上来，接下来的情况更糟糕。这位服务员忙着招呼其他的客人，我们等了15到20分钟才拿到甜点的菜单，结帐时又一次经历了漫长的等待。

我对个中奥妙知道得清清楚楚，想给她10%的小费。克拉丽莎却不同意。这家餐馆的菜品相当不错，她还想再来。小费太少会让他们不高兴。因此我们达成了妥协：15%。

我们这种解决方式并不少见。康奈尔大学的林恩说，当人们得到恶劣的服务时，他们给的小费会少一些，但不会少太多。他说，外面出没出太阳对小费多寡的影响和服务质量好坏几乎是一样的。

I usually tip 20% for excellent restaurant service, 15% for solid service and 10% for bad service.

I thought I was being generous. Turns out that makes me, at best, an average tipper.

Tips have been on the rise for some time. During the 1950s, people commonly tipped 10% of the bill, says Michael Lynn of the Cornell University School of Hotel Administration. By the 1970s and 1980s, the standard tip had risen to 15% of the tab. Nowadays, people commonly tip 15% to 20%, with the average tip about 18%.

Why are tips rising Dr. Lynn, who's written more than 40 papers on tipping, says that people tip to make a good impression on the server. 'If I want the server to really like me, I have to leave an above-average tip,' he says. 'And if I want the server not to dislike me, I have to leave an average tip. That dynamic leads to an upward trend in tips.'

There's a lot of money on the table. Americans tip about $42 billion a year, estimates Ofer H. Azar of Israel's Ben-Gurion University of the Negev, who studied tipping while getting his doctoral degree in the U.S.

Despite the economic crisis, don't look for tips to get smaller anytime soon. Drs. Lynn and Azar say the same social-acceptance factors are likely to keep pushing tips higher, albeit gradually.

'These changes are over decades, not year to year,' says Dr. Azar. 'I don't think in five years that 25% will be the norm.'

Despite my cost-cutting ways, I actually have sympathy for the restaurant help. My last job before becoming a full-time journalist in 1980 was working as a busboy in a French restaurant in California. Busing tables was grueling work. The waiters would give us a share of their tips, and the extra $15 or $20 I took home on a Saturday night was big money to me back then.

The restaurant was owned by Iranian immigrants during the Iranian hostage crisis. (If it sounds like something out of a Peter Sellers movie, that's what it felt like.) Business, to put it kindly, was sporadic. One Sunday night, the restaurant scheduled only one waiter and one busboy, me. For some reason, we got a run of business -- far more tables than we could handle.

This particular waiter had been at it awhile. He told me there was no point trying to give good service to everyone. It was impossible, and we would just irritate everyone. Instead, he told me that he was going to pick certain tables for good service (and good tips) and he'd get to the rest when he could. So that's what happened.

A waitress in an Italian restaurant in New Jersey recently pulled the same number on my wife, Clarissa, and me. Our dinner took forever to come, and it got worse from there. As this waitress rushed to help other customers, we had to wait 15 or 20 minutes for a dessert menu, and there was another long wait for the bill.

I knew exactly what was happening and wanted to tip her 10%. Clarissa nixed that. The food in the restaurant was quite good, and she wanted to come back again. A lousy tip would get them upset. So we compromised: 15%.

Our solution wasn't unusual. Cornell's Dr. Lynn says that people tip a little worse when they get bad service, but not dramatically. 'How sunny it is outside has as big an impact on tipping quantity as does the service quality,' he says.