Or how about this analogy. You buy 1000 DRYS shares at $3 per share as a long-term investment. You check the price every quarter and see the price hasn't changed much so you go about your daily business.
A year later, you check the quote and it's at $6 a share!!!, a double bagger (pun intended), so you quickly logged into your account, and without looking, you hit Close Position. Immediately after, you realized it was a negative transaction because what was left wasn't enough to cover commission.
Not-so-fun-FACT - You would have experienced the above if you bought any amount on May 10, 2016 and sold it May 11, 2017.