5301991f_and_The_Art_of_Breaking_Things__detailed_explanation
[signal] Pasted smile [part of body] mouth [possible meaning(s)] faked smile [detailed explanation] 
A pasted smile is one which appears quickly, is fixed for longer than a natural smile, and seems not to extend to the eyes. This typically indicates suppressed displeasure or forced agreement of some sort.
“I pretty much try to stay in a constant state of confusion just because of the expression it leaves on my face.” – Johnny Depp | Zen and The Art of Breaking Things
detailed explanation