Re: But WAIT, there's MORE!
Basically, Booster Gold wanted to go back in time to save Ted Kord from dying, but Rip Hunter kept insisting he do a bunch of other time travel-related saves first.
Except that he had Booster try and prevent Babs from getting shot as a way of proving to Booster that some things couldn't be changed. No matter how many times he tried, Booster couldn't prevent the Joker from shooting her.
It was...really kind of a crappy thing for Rip to do, putting Booster through that, and it's crappy of them both to be messing around in other people's pasts like that, IMO.
(And considering that Booster has met up with Babs in her past again since then, I am waiting for the inevitable moment when he gets an intimidating message from Oracle insisting that they catch up.)