why give up now?

so its super late.. I have been sleeping well what so ever.. but tonight that is not the reason why i am just getting to bed now.. lately I have been addicted to doing puzzles.. yes thats right i said puzzles! I know i know I am only 27 years old.. what am i doing.. doing puzzles. but it has really has become a great source of therapy for me.. Today/tonight my friend karen bought out a new puzzle.. a much harder puzzle then we have been doing in the past.. its a thousand pieces and is only black and white.. its so hard.. around 1:00am after working on the puzzle for hours already karen said to me i am going to work until 2:00am I have put so much time into this already how can i give up now..

I stopped.. and thought why? why give up now.. I was not talking about a puzzle i was thinking more on a personal level.. but.. we work 7 hours on a puzzle a put so much time and effort into it.. we did not just want to say screw it and give up, take apart all the pieces apart and put them away. We decided to keep going.. Not long ago i was told by someone that they were ready to just give up on something they have been working at for 7 years 7 YEARS... to just give up walk away.. and leave just drop it just like that.. we did not stop at a puzzle because we put so much time in it.. WHY do people just give up when so much time is invested... i just don't get it.. it hurts my heart..