What is the Half-Life of Shtick?

This morning I presented my research to an undergrad class. I've done what is more or less the same presentation four times now. Being research, the presentation is dry by definition. There are ways to spice it up with pretty pictures and whatnot, but presenting scientific findings is really contingent on one thing:

How smooth are you?

Fortunately, I'm very smooth. Not in real life, mind you, but in the setting of a short lecture, where my audience is semi-captive and semi-conscious, I have the uncanny ability to keep them entertained and attentive.

Rewind 7 (yes, SEVEN) hours. Walking back from Karaoke with Will, the topic of gimmicks came up. Plastic cups as fake breasts; done to death. Flipped-out screaming ad-libbed rants; approaching done to death (you know who you are). Mr. Roboto; somehow played-out after just 2 performances.

Fast-forward back to my lecture this morning. Sitting in the classroom, waiting my turn to present, I asked myself, "will I make the same joke as I have at the previous three conferences?"

The joke goes like this: "Hi, my name is Don, I'm from Rutgers University, and today I'm going to talk to you about my research into the Effect of Ice-Cream Consumption on Graduate-Student Happiness. We found that the more I eat, the happier I am. [pause for laughter] But you probably want to hear about my work with the use of Force Myography blah blah blah..."

Seems lame, but the audience is so accustomed to "Hi, my name is ____, and I'm going to talk to you about [read the Title verbatim]" that my little gimmick wakes them up. Seriously, it gets 'em every time.

This morning, though, I simply couldn't do it. I couldn't bring myself to use the same lame joke again. I knew, of course, that nobody in that room had heard it before, so it wasn't yet overused for them... but it just seemed so played out, in spite of its previous success.

The shrinks out there could probably explain in technical terms why our own experiences can overwhelm our perception of a concept that is, at least rationally, completely fresh. In fact, I'm pretty sure the term is hysteresis (which has nothing to do with hysteria or hysterectomies).

The big, important questions are: Are we hyper-sensitive to our own gimmicks? Are we sacrificing good shtick for no reason?