Team spirit

Grandma and I challenged Matthew to a game of Bomberman.  Matthew got a computer partner to keep things even.
The first two games Dad and Grandma were shut out 3-0, 3-0.  Matthew was thrilled.
The next two games the old farts took 3-1, 3-2-1.  And recriminations ensued.
"RRRRRR!  He keeps making me die!" Matthew complained about his partner.  "He ALWAYS makes me die!"
A few minutes later: "Haha!  I killed Red! [his partner]"
"Why'd you do that?  You would have won the game if you hadn't killed him."
"That's cause HE MADE ME DIE!"  Matthew's face is fierce and he's literally shaking his fist at the screen.  I wish I had a video.
I never was able to explain that if you want to win (and oh boy, does Matthew ever), killing your partner is suboptimal play.  Even if he killed you first.  (And it's more accurate to say that Matthew walked into his bomb, than that Red killed him deliberately.)
So if you're ever on Matthew's team... watch your back.