Is "Fake it 'til you make it" an acceptable Buddhist behavior? Does Buddhist psychology view the concept of "fake it 'til you make it" as an acceptable social behavior (eg, cheerful behavior rather than stressed behavior, or calm behavior rather than emotional behavior)?

For example, I recently attended my first meditation retreat (a weekend event). I was overcome with emotion a couple of times during meditation practice and teaching sessions, with quiet tearfulness. Also, during the sharing time, at the end of the retreat on the final day, I wept as I finished my expressions of gratitude to the teacher and group.  

Should I have restrained that last public display of emotion? Was that display of emotion an ill-timed expression of ego/self, and, therefore, according to Buddhism, best to be avoided?
The idiom "Fake it until you make it" or the recent turn of phrase "Fake it until you become it" used by Amy Cuddy in a Ted Talk about body posture and how it effects your psychology seems to focus mostly on the concept of confidence: http://www.ted.com/talks/amy_cuddy_your_body_language_shapes_who_you_are

In that sense in the west there seems to be an interesting idea that confidence is key to success and therefore one should be confident at all times. This is of course not possible and there is where this idiom comes in. The idea is that if one act and behaves as if one is confident, one becomes more confident by way of training. in other words: "embody as best as you can, that which you want to be."

If taken in this way the idea may be applicable to Buddhists, not waiting for confidence, not being paralysed by uncertainty but practising being the person you want to be. Note that this is not the same as ignoring ones feeling or suppressing it. Nor is it a mode you don't allow yourself to fail.

I agree with the other answers that you did not act inappropriately. As long as one does not flinch because of it, or see it as a failure.