I suppose only "complete fkn prick" would be dollar cost averaging during a downtrend.
When you stop looking at bitcoin as a get rich quick super volatile trading all or nothing gamble every transaction, and start looking at it as a long term investment that makes up part of your overall investment strategy, you come up with entirely different ideas about what is a good idea and what is a bad idea.
I would give one of my kidneys to be able go back in time to June 2011, and dollar cost average my entire life savings from $30 all the way back down to $2. And then HOLD all my 1000's of coins all the way to today. Of course I would have been laughed at by family and friends, and the troll day traders in 2011 would have told me I was a complete fkn idiot. I would of course kept on buying more coins even at the lowest points because I am stupid, all to the laughter of the bears, naysayers, and trolls. All would have had pity on me in 2011. Children would have pointed, laughed and spit on me as I passed them in the streets.
Based on what has transpired since then, I don't think I'd be alone in my time travel fantasy. And those that don't think it will happen again in the next 2 years should really get out of bitcoin now and go do something else.