Interpretation is dealt with on many levels with the brain; Speech is the top level.  Many people have the most tactics built up around speech, that’s why it’s necessary to make the most of your unspoken skills in order to get your point across. Body language is a big part of this – if you’ll notice in acting classes, peoples’ unspoken languages are treated just as importantly as their speech.

Getting someone to think what you want is best used when dealt with unspokenly – saying ‘this is cool’ is a theoretically good way to get someone to pay attention to some particular point but when delivered subconsciously (having fun with something demonstratively) the message is unaltered because it doesn’t breach the high totem of consciousness and require the back interpretation to affect the person - things like embarrassment and pride are 'traps' brought up on this level and can be easily subverted by the unspoken language.

The disadvantage of this is only limited by the confidence of the person using it. I know I sometimes have a hard time believing I’ve affected someone if I don’t have sure signs of it. Emotion’s a tricky thing.. Knowing you’ve accomplished it based on visual cues alone is misleading and unsure, but it’s the double-edged sword with this. You’ll never ever be told by someone that they’re mad at you when they are, so don’t expect such simple things. The emotions that are covered up the most are also the deepest, so embrace the skill as you learn.