People have been feeling betrayed and regret when they've missed the best part of buying it at low but when it starts to dump, the joy kicks in.
That is what JOMO do. When your coins that you want to buy goes higher, you feel bad for missing out but when the dump happen then you feel happy .
I think the altcoins are not the only coin that can dump because bitcoin itself happen on that most times but the difference is that in the case of bitcoin, it reverts faster than altcoins.
All cryptocurrencies are bound to go up and down but it's unfortunate that many of these altcoins are bound to go down forever because there will be a few of them to remain in the future.