You've jumped into Crucible. You may be there because you enjoy PvP.  You may be there because you have bounties and gear to work on.  Whatever the reason, many of us jump into Control as our PvP of choice.  It's a team game and the strategies are pretty straight-forward.  Capture two of the zones and then hold them.  

Why not capture all zones? Surely you must win even faster if you do that!   

And this is the thing...

If you capture all three the spawn "flips", which means that instead of the enemy coming from "in front" of you, spawing at the zone they control, they will now come from behind you (potentially), throwing off your entire team. This "flip" often results in the other team gaining possession of more than one zone and well, you see the problem. It's normally better, especially in random groups, to just control two zones and hold back the enemy horde. 

Many players don't consider this, and hence this great bit of humour by /u/Rabbidscool on Reddit.