You know whats bullshit, its a staple in a lot of jrpg's too.
Fights you're forced to lose. Its fine on a fresh playthru where theres no way for you to be strong enough to actually beat these unwinnable fights.
Its complete horseshit though in jrpg's that have a newgame+ where your strong enough to curbstomp bosses your forced to lose and the game doesnt acknowledge it. I always found that frustrating.
The Disgaea games are one of the few instances where t game will ackowledge your victory, usually in the form of a bad ending.
Like in Disgaea 2 when you Fight Laharl on the tower, if you beat him, he gets mad and blows up the planet.
Or when you fight Etna in ithink it was chapter2, maybe 3, if you beat her, the game ends and you get the demon lord title.