If the average person cannot explain to you what the blockchain is, how is the recent level of bitcoin a bubble? 

I've seen this before in the commodity markets and although we're likely to see volatility that's uncommon in the markets, you can study the spread of viruses to get a better feel for this type of growth. 

You can control the effect of volatility in your portfolio by decreasing your position size. You can further minimize your loss potential by using low to no leverage. 

If Amazon or Walmart decide to take a crypto currency as a form of payment, demand for the underlying will explode as none are currently considered mainstream in terms of usage despite a steady stream of headlines about them. 

Once this happens, I believe the best opportunity for adding crypto currency risk to your portfolio will be via an investment, not a trade. No crypto currency has gone mainstream yet, so all the talk is about "the trade" and that means the majority of people will leave the majority of the money on the table. 

McDonald's went public in 1965 around its 10th anniversary. It was not mainstream until 10 years later and it still had a ton of growth to go. For example, they did not begin serving Chicken McNuggets until 1982, almost 20 years after IPO'ing.

If you'd bought 25 shares of MCD at the IPO price of $22.50 (a investment of $562.50 in 1965), your position would be worth over $3 million today at a price of $175 per share and adjusting for splits. That's more than 5,400 times your money over the same time period. That's also 50 years ago, so who can tell how they would have handled the position. MCD has split 12 times since the IPO. 

Sure there had been some great trades along the way. There have also been some dead periods too, but when people who have not been trained to time the market or to trade, they leave the majority of the money on the table. 

I think the reason is the people like to seem reasonable. Let's say you invested in MCD and you sold your entire position when it had doubled.

Maybe you felt at the time you didn't want to be greedy. Or you feared giving it all back...

What is the opportunity cost of that lack of emotional awareness or mindfulness around your process (or lack of one)? 

Where is the opportunity in bitcoin or any crypto currency at this point? While I believe there will be parabolic moves, great trades, big drawdowns, the best bet is to invest in it and hold it for 20 years.