For me my own greatest regret was selling my coins been giving to me for participating in bounty at ico price but now the coin have little moon to $5 deal feel like crying now.
That's gonna be a problem if you cannot let go of it.
Although it's just a bounty, it has the same value as investors coin, we sell because we need to cash out but the best way to do it is to sell a portion
and just hold a portion also for your future.
Anyway, it's all gone now, just learn from it, there will be more coins to be earn.