What does it mean to "collect oneself"?

I would say it refers to being able to sit down and clear one's mind, think rationally instead of letting an emotion/stress/problem throw you off balance one way or another. It can also refer to perseverance in the face of difficulty.

I think of it as gathering ones thoughts, becoming self-posessed, recomposing oneself to a balanced state, usually prior to doing something challenging.

My understanding of the expression "to collect oneself", is that it is a reference to being in an emotional state, for example: crying, and needing to regain one's emotional equilibrium before proceeding, for example: going into the next room to meet people.

For me it means I have to start from scratch. Get my bearings. Where am I, Who am with, What are we doing, What topic are we discussing, What was my next point. Usually when I go on the blink, I only have to go as far back as recollecting the topic and my point. Sometimes, I've covered half a dozen topics of my own between replies, and need to pinpoint which if any contained useful or entertaining responses.
When I was in my 20's and didn't get much sleep, waking up involved pointing at everything and getting a fix on the physical structure of the universe. For the first 15 minutes it would generally be a hybrid reality containing the physics of my dream.
If I were to have developed a personal interpretation of the phrase at this point in my life. It would mean something much different: something along the lines of becoming one with all my sensory feedback, and choosing the flow-structure of that interaction.

Excellent survey.
These other definitions apply to me as well. The most common however is maintaining a train of thought after a distraction.
Some of my favorite people are gathering here.

I always think of it as meaning the person needs a moment to organize thier thoughts.

I think it means to stop and "get my crap together".
Stop and think and take a deep breath. If I was really stressed or had just heard some bad news, I might need a minute to collect myself.

I can't explain it...you know, collect yourself...

Count to ten...calm...breathe breathe....

cool
collected
resume life

I don't know

Depends on the situation, to become more anal, regal, serious, professional...

It means to gather one's thoughts and composure, and regain mastery over oneself.

You continue to fascinate me since I've paid you some attention. If I give you the benefit of the doubt, I take it you don't collect yourself, and are cynical of those who do.

To me it means to assert control over whatever weird autonomic functions my body is going through, and try to focus my mind on the task at hand. Sometimes you just suddenly realize that you're operating on autopilot and you hadn't even noticed. Collecting yourself is turning off the autopilot.

Get ones thoughts straight.

center yourself, get your sh*t together, calm down and get back into a positive state, etc.

So far, your description is closest to mine. The autopilot thing is my biggest problem. It makes me sick!

(& joachim) might autopilot be absentmindedness, or out of mindedness.
eg. absentmindedness could mean putting the keys in the fridge, or suddenly realizing that you're brushing your teeth during a TV commercial, an appropriate thing to do, but nothing you remember choosing to do.
out of mindedness would be something that normally entails high intellect & sophisticated decisions like computer programming, yet you are performing the task just fine while your awareness is engaged in an altogether different activity like prayer or contemplation.
There's some overlap. I known both, but mostly the unpredictable absentmindedness while my mind was engaged in drifting concerns.

Certainly not absentmindedness. More like going through the actions of life, without thought, or 'internal dialogue', which I value highly.

Interesting, there's rarely been a minute in my life lived without internal dialogue. I consider it absentmindedness when, as is generally the case, that dialogue has nothing to do with my physical activities or surroundings.
Actually I've had a feeling from the onset that this was your state. As I imagine it, it is like a dream state. I can imagine three things that that might make you desire: crisp critical thought or contemplation, satori (non-judgemental rich immersion in the senses), congruity of thought with environment. The latter exists in both the mystical and non-mystical version.
I suspect you seek a greater sense of substantive connection. I can assure you first hand that a constant inner-dialogue does nothing to promote that, it even detracts from it. Thought is no less a cul-de-sac than feelings. My astrological influences are fire and water. I take it yours are water and earth.
Your premise for the survey was right on. We think people think more or less like ourselves, but in fact there's a vast array of consciousness, and only the appearances are similar. You and I, though quite different from each other, are somewhat rare in that we have a mystical consciousness, though not as rare as you think.
I'm glad you wrote this survey.

I was definitely something I needed. What's funny was that people voted 'hopelessly flawed' in qualifications. That tickled me.

I can relate very well to what you (and joachim) mentioned. I can relate as well to the two types of "phasing out" that Kristal_Rose mentioned. I never associated snapping back to reality from any of these with collecting myself though, more reviving.

Could you elaborate on that last sentence?

It means trying to amass as many copies and permutations of oneself in one place as possible.

Well said.

To pull yourself together, to calm down after being upset.

Pull yourself together, get back the cool you should have been keeping.