Don’t look a gift horse in the mouth.
Another partial quote that is often misinterpreted to allude to a present changes when the entire quote is read. The meaning is clear that it has to do with manners and a tip.
‘Tis civility wins the gratuity, and those who expect them should take graciously what is given them and not look a gift-horse in the mouth unless they know for certain that the winners are common cheats and have won unfairly. Cervantes, Don Quixote
If you do not change your direction you will end up where you are headed.
The captain of a battleship has just been informed by a lookout that a light has been spied dead ahead through the fog in the distance. The captain orders a signal sent by flashing light. “We are on a collision course, advise you alter course 30 degree port.”
The signal is straight away returned, “Advisable for you to change course 30 degrees starboard.”
The captain ordered his communications officer to send back, “I’m a captain. You had better change course 30 degrees port immediately.”
“I’m a seaman second class,” came the reply. “You had better change course 30 degrees starboard.”
Now extremely irked the captain spit out, “I’m a battleship. Change course 30 degrees port now.”
Back came the flashing light. “I’m a light house.”