Exactly what the title says.
If bitcoin dropped to the price of a dollar (which we hope it never will), what would you do? Buy more and hold, sell? Buy a promising altcoin like ETH?
I personally would buy more bitcoin.
I will also buy more bitcoins @ $1 it will be a dream come true and fuck ETH. ETH is having unlimited coin supply so it will always decrease in price in future, but bitcoin having 21million coins cap will be safe heaven.
If price goes that low then people will go crazy for sure, either by panic or to buy as much as possible, it will depend on individual how he views and react to the situation.