When Cass was like Jason
4 scans from Batgirl #07. writer: Kelley Puckett, penciller: Damion Scott
Being to compared to Jason Todd, in the Batman mythos, is a Bad Thing. According to the orthodox editorial meta, being like Jason means being angry, badly trained, and reckless. Jason Todd is widely depicted as the Bad Robin - first he died, and now he's back, meta wants to make him "irredeemable".
It's generally admitted that Steph was like Jason. (Even Robins represent.)
This takes place when Cass has lost her ability to read body language and thus 'foresee' her opponents' moves. (She later regains it.) She's not used to it, so she takes a beating, and Batman pulls her out of the streets for a while and into a rigorous training regimen.
It doesn't go very well.
Cass is frustrated. She's never before been unable to do something, so it's one of the first times we see her being negative. But she's willing to push herself, even if she finds Batman's training process confusing and inefficient. And she keeps getting thrashed. Cass gets truly angry - snarling and scowling and completely disregarding that she has blood running down her face. Demanding to try again. And Batman freezes. Gasp shock and surprise. Cass makes a heroic declaration and is awesome; she makes a case for wanting to protect people - in a way that underlines her death-wish - and that prompts Batman to tell her about Jason. It's not just the anger. It's not disobeying orders, which is, while we're at it, one of Robin's traditional tasks - someone needs to call Batman out when he's on the verge of killing the bad guy. Note, in fact, how Batman does not fall back on those excuses to warn Cass off.
He just tells her what happened to him, and he does it after Cass implied that she would have no issue with sacrificing her life. Jason died after he undid his mother's bonds - the woman who had sold him out to the Joker.
Being like Jason means wanting to protect people so much that you forego protecting yourself.