This act is only logical to me in one way of greed. Because the one who have more greed, try to make profits from every trade regardless of market situations. No wonder, a lot of early or pro traders book big profits in their first trade but that could be due to luck. The real skills are when you can book profit from the second trade consistently.

You should perform the same level of analysis before the second trade like you did in the first one. You should not follow your emotions of opening another trade just because you make profits in the last one. Because when you made $10k profit in first trade then by flowing in your emotional sentiments (greed) you opened another trade and lost your profit of $10k dollars. I have a tip for you to perform DCA and diversification  which will decrease the ratio of loss.  

Everyone notices these things before opening any trade because analysis is not a one time step to do it's a prerequisites of every trade even you are trading in the same pair. Why it is necassary? Because market is so u predictable and depends on many fundamental and technical factors which we should keep in mind before taking entry in trades. I hope you will got my point.