Beware of people who are TOO nice...
Notice that I use the word "usually."
There are a handful of people out there who are genuinely nice and expect nothing in return, but they're the exception rather than the rule.
For the most part, people instinctively know that when they're nice to someone -- including giving them unsolicited compliments -- they're likely to create a favorable impression and put them in a good mood, thus making them more likely to say "yes" once a request is made.
As I've noted in other posts, the principle of reciprocity holds that when someone does something nice for us, we feel compelled to pay it forward in the future.
You see this all the time with waiters at restaurants who will butter up clientele in hopes of coming away with a good tip. For example, I've seen waiters and waitresses do everything from chat up my gregarious nephew to call me "boss" to literally flirt with me!
They're not being nice just because they're good people. They obviously have something up their sleeve.
You also see this principle in action at department stores, where pushy salespeople will try to endear themselves to you in order to land a sale and score a handsome commission.
But such behavior isn't limited to those who have a financial incentive to get in your good graces.
We see it every day with people in our immediate social circle -- from friends to coworkers.
I'm sure you've noticed someone you know being unusually nice one day, only to ask you for a favor an hour or two later. This is no coincidence, folks. It would be in the realm of possibility to say that some sly individuals plan this out days, if not weeks, in advance -- depending on the request.
On the surface, a compliment may seem like a purely unselfish act, but why bother if you know that person has nothing to offer in the future?
If you know you'll need him or her to finish a project on deadline, get to the grocery store while your car is in the shop, or watch your kids for you while you enjoy much-needed alone time with your spouse, you're much more likely to play nice.
Once you no longer need the person, sucking up to them doesn't really serve a purpose.
Sadly, even the nicest gestures often come with strings attached. So be wary of people who only seem nice when they want to pry something from you, as they're unlikely to change their ways.