Flattery - honeyed words, sweet talk, smooth talk, buttering up, blandishment, excessive or insincere praise.
Encouragement - inspiration, motivation, support, morale-boosting, championing, promoting, furthering, nurturing, help.
Right off the bat we see which word feels more genuine and more effective. Yet, I think we still get confused as to how and when to use these tools of communication.
In my opinion, flattery is useless. If it were a literal tool in my toolbox I'd throw it out. There are things you can replace it with that will do the job so much better. For example, if you are using flattery in order to gain influence with someone, like a boss or a leader, you are using the wrong tool. People are perceptive and they will discern very quickly when you are being insincere in order to gain favor. Also, those around you who are at your level will resent your shortcut ways to get ahead. You will be dubbed the "brown-noser" of the group and that is a difficult label to shake once it's been given. Instead of using flattery, use genuine interest (encouragement) and observations to gain influence with people. For example:
"Wow, you handled that meeting with a lot of wisdom, I think I learned a few things watching you."
"You seem to lead with great confidence, I like that about you."
"I find it very easy to work under you, thanks for being a great leader."
The key is to only say it if you really mean it. And, choose an appropriate time to deliver your observations. Don't over-do it.
Another common scenario where people use flattery is when a friend or loved one asks them for their opinion, and they don't have the heart to tell them what they really think. So what are some ways to get around telling someone the blunt truth that may hurt their feelings? Let's say a stay at home mom decides to take piano lessons for the first time in her life. She plays her first song for you, and it's terrible. Here are some things you could say that would encourage, rather than flatter:
"I think it's amazing that you are stretching yourself and learning new skills instead of just living an ordinary, day to day life."
"I'm really impressed you are pursuing something like this, is it everything you'd hoped it would be?"
"Is piano your preferred instrument? Does it bring you joy to pursue this?"
Where it gets different and more specific is if this same person says they want to take out a $50,000 loan to cut a new album or start a career as a musician. Then you may have to sit down with them and say, "I'm not sure this is the area you've been naturally gifted in, are you sure you want to invest in something so uncertain?" Or, "To be honest I don't see you having a successful career in music, but I do think you are an amazing parent. You have so much to share with the world in the ways of raising good kids, have you ever thought of developing that more?"
Flattery is a dead end. If you tell someone they are good at something they are not, you could lead them on a wild goose chase, or at the very least, allow them to keep believing a lie. Encouragement tells the truth, but in a way that takes the spot light off what "sucks" and puts it on what is amazing. Everyone has an area they shine in. Not everyone was meant for the stage, but everyone has greatness in them. It doesn't take a genius to point out the flaws. A teacher of mine used to say that people are like gold mines. Keep digging until you find the gold. Anyone can find dirt, but why stop there?
How about the infamous question, "do these jeans make my butt look big?" What do you say if they do? I always like to say, "that's not your best look, I think that other outfit compliments your body shape much better." Or, "Well, your legs are your best feature, so I would wear something that shows them off" instead of "your butt looks huge in that!"
It feels like people are either like Simon Cowell, and just say what they think without any regards to someone's feelings, or they swing to the other side and they are Paula Abdul saying ridiculous things that don't even make sense in order to be the "good guy."
My challenge to you is to use balance, truth and encouragement with your feedback. Don't be lazy by just saying the first thing that comes to your mind, and don't be a coward and basically lie to avoid awkwardness.