I’ve got this tendency that’s absolutely crippling at the wrong moments.
I can perform (give talks, speak coherently about my research-subject-of interest) pretty well in front of a friendly or friendliness-status-unknown audience. But, I have huge trouble with the big-shot audience- if I KNOW they are a big-shot audience, or performing (either on a test or in one of the above situations) in situations that I’ve built up a bunch of internal pressure about.
I first realized this when I was in college I took a class I really loved, I mean REALLY loved- it was called comparative vertebrate anatomy or something like that- taught by a very well known professor. I loved the class, I found the evolution of vertebrates and seeing how structures changed from stage to stage quite fascinating. And it was the first time I took a course that taught embryology, anatomy, and palentology,… so it really opened my eyes to an integrated view of biology. The professor was awesome- and I think it safe to say that that class is big part of what put me on a path to where I am in my career and interests today. It should be clear by now that I loved this course, and I was very motivated to do well. But God- did I choke on the tests. Not because I didn’t study for them, I studied like mad, I worshipped the professor- I just put a ton of internal pressure on myself and totally flipped myself out at the wrong moments.
This same thing happens to me when I’ve got (for example) a national academy member in my office. I just choke, I can not make a sentence that is even moderately intelligent. Or maybe I can, but it sure doesn’t feel like it. All of the outgoing, self-confident parts of me just seem to melt away. This is NOT what you want to happen when you are chatting with a national academy member!! If I don’t look at their CV first, and I don’t let their CV intimidate me- I’m ok.
I know all of you that know me in person can’t believe that I’m saying this right now, but it is true- even I get stage big-shot fright.
Blue Lab Coats 
I will admit to being readily intimidated by some of the greats in my particular field, even though when I meet them (as I have occasion to do) they have always been very kind and thoughtful. For me, I think it’s just a matter of time before I actually consider myself their peer. Perhaps it’s the last vestiges of my graduate and post-doc days.
TomJoe- I’m making that interesting transition from the kids to the adults table. But that doesn’t help me get over the intimidation of big-shot in my office. Although you are right 9 times out of 10 they are awesomely nice.
I feel the same way when talking to big shots or asking them questions after their seminars. The last episode occurred when R. Losick visited my grad. department to give a talk. I pretty much have almost every paper ever produced by that lab memorized and I had been looking forward to his talk since I found out about it. The talk was fantastic, and even though I had several questions that I wanted to ask him, I just couldn’t bring myself to raise my hand and ask. Then I hear a few of my questions get asked by other members of the audience and Losick replies, oh, that is an excellent question. At that point I was ready to band my head on the back of the seat in front of me.
Microbiologist xx- I know the feeling. I encourage you to ask… and if you just can’t do it with an audience… then go up to the speaker afterwards and ask one-on-one…
The last episode occurred when R. Losick visited my grad. department to give a talk.
This reminds me of the insight I had as a grad student that cured me of this affliction: my lab was at the big Drosophila conference and everyone was cowering in awe of the big names as they wandered. Suddenly it dawned on me. “This isn’t Michael Jordan (1). It’s X who had a couple of Cell papers. No one outside this auditorium cares who she is.” And I started walking up to every “big name” (2) and introducing myself.
The point being that I have no idea who “R. Losick” is, so why should you be any less unintimidated by him than I would be?
1. Youngsters, replace with LeBron James to get the point.
2. Most of whom got another Cell paper or two out the pipeline they had running at the time and I haven’t (from my position in a different field now) heard of them since.