(CNN) -- Professional travel reviewers are like prickly old movie critics -- once they've done enough traveling, dining and lodging, they can become weary and entitled, taking for granted the joys that accompany nightly turn-down service or unlimited bread sticks.
That's partly why user reviews on sites like TripAdvisor, Yelp and Google+ Local have become so useful.
But user reviews, too, have their shortcomings.
Woody Hayes, the legendary Ohio State football coach, once opined of throwing the ball, "There are three things that can happen when you pass, and two of them ain't good."
Likewise, there are five kinds of online user review -- prompted by five basic motives -- and four of them are almost completely worthless.
Make sure you know which is which before you stake your next global game plan on TravelFreak1979's portfolio of reviews.
Motive No. 1: Wrath
Whether it's anger over a disappointing product or service, conniving competition or a disgruntled former employee, this makes the user less a reviewer than a vigilante.
A reviewgilante, if you will.
Telltale signs include:
Nothing good to say
A-Rod has great taste in suits.
Chernobyl has a delightful little self-lit café.
There's almost always something good that can be said about terrible things, and any reviewer who can't summon one is probably still working out high school angst.
Complaints outside the business's control
Legitimate criticisms about environmental noise or area safety can be helpful.
Bellyaching because a fellow patron's suicide leap "spoilt" your vacation karma, however, is not.
"Avoid this place!" "Don't eat here!" "Stay away!" You're not the boss of the Internet, JDWAG2309.
Chippy travelers with Napoleon complexes can find condescension in a clothing label, so any service that's not accompanied by groveling is going to earn a sternly worded tirade.
If you read something to the effect of "... our waitress smirked when we thanked her for deigning to bring us another round of gravy boats ..." that reviewer doesn't need dinner, she needs a prescription.
Foremost among the complaints warranting a one-star review of the second highest-rated hotel in Sydney: a king bed that was really just two twins pushed together and an iPad that wouldn't turn off.
If room service gets the wrong reviewer's white truffle and caviar kobe burger wrong, there's going to be hell to pay.
Motive No. 2: Euphoria
The flip-side of wrath, euphoria is the result of an overabundance of tittering satisfaction.
Whatever the reasons for their extreme joy over a complimentary bowl of beer nuts or an extra towel, these people should be avoided on- and offline.
Telltale signs include:
Nothing bad to say
Kate Middleton had eczema.
The sound from a Stradivarius is the result of asymmetrical flaws in its production.
There's almost always a hole that can be punched in even the most perfect things, and any reviewer who can't fathom one isn't sharing the same reality most of the rest of us live in.
Experiences no one else will have
It's truly awesome that management took such great care of you.
But remarking, "The desk clerk is from my same village in Nottinghamshire, so he upgraded us from a supply closet to a 24-room villa!" is a one-time-only experience that's just distorting the curve for the rest of us.
Where it's hard for reviewgilantes to find anything good to say about a place, euphoriacs are so full of gratitude they credit businesses with benefits they had nothing to do with.
Take a five-star TripAdvisor review of the UK's Depa Indiana restaurant titled "19 yrs ago, had a curry here & gave birth that same evening :)."
Unless this observation actually is relevant, in which case this restaurant, too, is to be avoided at all cost.
Motive No. 3: Profit
According to a Harvard study, 16% of Yelp restaurant reviews are fake.
Telltale signs of a phony review include:
It's the author's only review
Contribution counts beside each TripAdvisor and Yelp review hint at whether a user is being sincere or just popping in to prop up a business.
Words real people don't use
In their zeal to liven up the garden-variety contributions of real reviewers, fakers use lofty ad-speak words like "breathtaking," "succulent," "unparalleled," "mouth-watering," "sumptuous" "thrilling" and "fahrvergnügen."
Life!!! Just isn't!!!!! This exciting!!!!!!!
A Cornell study found that fake reviews center more on first-person narratives, like details about a travel partner and reasons for a trip.
Real reviews focus on specifics like bathroom size and pricing because they're boring and useful.
Admissions of fraud
It's not often someone confesses to getting kickbacks for their reviews, but it sure is appreciated when they do.
Magic Smile, one of the businesses implicated by the New York State Attorney General's office in its investigation of fake Yelp reviews, features this glowing endorsement: "I'm getting a free touch up for reviewing them here on yelp and that is just very cool!"
Motive No. 4: Status
The most unseemly of all motivations -- yes, even more than profit -- is that of the user who derives a kind of online celebrity from the number of reviews they've written.
Telltale signs include:
The Hunter S. Thompsons of TripAdvisor, power users often make their reviews about themselves.
One TripAdvisor alarmist, after raining praise on the food at London's Gordon Ramsay restaurant, closed his one-star review with a diatribe about babies, demanding "that seats in this august room are only given to guests who can speak. Gordon... Its either the babies or me." [sic]
It's the author's 10,000th review
Professional writers get paid by the word and they don't write this much.
Everyone's a comedian.
Except that almost no one is a comedian.
Cute, snarky and glib, these reviews are packed with more rim-shot one-liners than a ... aw, hell, now they've got us doing it.
Motive No. 5: Duty
Awarding three stars may be like kissing your sister, but somebody's got to occupy the reasoned middle.
Here is where, without agenda, workmanlike reviewers toil thoughtfully and thanklessly for the betterment of all mankind.
These, finally, are the reviewers to trust.
Telltale signs include:
Conscientious reviewers understand polarity -- that there are positives and negatives associated with everything.
Even a review titled "Found a tooth in my food" was prefaced by "Usually they have good food ..."
One reviewer who's been to Hedonism II 17 times still hasn't given it more than four stars.
Nothing in this world is one-size-fits-all, making distinguishing details about the reviewer helpful when trying to get your bearings as a reader.
A qualifying hotel review might read, "I'm 250 pounds, so I found the bathrooms at the Smurf Hotel a little cozy for my tastes ..."
That's it, actually
Despite what you may have heard, sober objectivity when reporting is remarkably simple.
Jordan Burchette has edited and written for several dozen magazines and websites including ESPN, Comedy Central, Thrillist and Woman's Day.