It makes me nervous to be part of a market in which the main price-driver may be nonsense.
Just out of curiosity, then why don't you sell and find another market you feel more comfortable with?
I do sell, have been selling these last days.
However, I also like the idea of Bitcoin. Were it other forces driving the price up, I might have continued holding the same amount. This is why I have to find some optimum amount I still want to keep -- which takes time and analysis I might as well post. I see a small but real probability price does jump very high, through a large bubble or reaching critical mass. I'm not sure though whether the former is more help or hindrance to the latter, since I don't think hoarders contribute much to synergy effects, while they do contribute to price instability.
Should it keep going in the same fashion, in effect I'll have to do as you said and leave with at least the funds from the sales. I don't change my mind fast enough to buy back at such rapidly rising prices.
Then again, I'm reluctant to move out for another reason. This kind of (to me) uncomfortable up-spikes happened three times already and each time it just cooled off, crashed or busted and gave me some extra profit plus an opening to buy back in. In two of the cases I even ended up with more Bitcoins than before plus profit; in the third with a sizable profit. Even the worst of these turned out a good deal compared to other options.
Remember that last time we had speculation mania of this size, price crashed to the 16th fraction of the peak, at less BTC in circulation than today! Even if the market grew by a factor 4 since then and better traders cancel out the effect of minting, there's a real chance for a bust. From my perspective, the hype does not increase my personal valuation of Bitcoin by more than a factor 4, and I feel I lack diversification since the price hike. So the natural choice for me is to ponder on Kelly's Criterion to determine with what fraction of my coins I should bet on a crash.
Also, I'm not a speculator with a long history and interested in how well I can do. So short-term speculation is interesting, even with less remaining coins. There has to be money in the game to make a real benchmark. Otherwise it's way too easy to cheat on yourself.
So, uh... I guess the discomfort is mostly when I have to make a tough call on an amount that matters to me. I'm not rich, so the price hikes made Bitcoin more than a small game for me. (Which is also a reason to diversify)
(And I'm a little attached to the community. Have been doing funky stuff and crazy deals with various people, totally walking off would be hard either way. )