Buy when everybody is pessimistic.
We might not be there yet but it's close.
I'm still living in Bitcoin euphoria, since the CFR took an interest in Bitcoin only 2 of the 4 big predictions have come to pass.
1) the collapse and or outlawing of key exchanges
2) the arrests of known Bitcoin personalities
3) a media smear camping demonising Bitcoin.
4) a collapse in the price. (I'm still coming to terms with Bitcoin leaving double digits)
To be honest the only thing that can collapse the price IMO are the week hands, (non believers) stolen Bitcoin and whales redistributing/ facilitating future wealth growth, and I think a lot of coins @ the new order of magnetude have already been flushed.
I welcome a drop but if it happens it may take time or if it is quick it will kick some new big players in the balls, if it happens.
I've got no much fear left in me, to be honest.
I've survived only April 2013 bubble with actually having coins though I watched the stuff in 2011.
The biggest fear I had with BTC is how the USA will react it and all our fears about Bitcoin going to zero were around that point last summer.
As soon as USA approached Bitcoin and announced to make it legal, I see any price drop as usual market movements. There are bear markets, there are bull markets, we might make some money in each of them or lose in downtrends but Bitcoin is here to stay and that's all I care about.
If there is one fear I have is about Bitcoin becoming irrelevant due to some superior technology but I think we have some time until that happens.