i wouldn't call a fish 'stupid' because it's aggressive nature killed fish you put in with it that were not compatible.
as for breeding, just buying two juvenile angels will not mean you'll get a pair for sure. best to get a small group of at least 6, wait for two to pair up, and then remove/rehome the rest.
i personally would suggest reading up some more on breeding fish, angels in particular, before you decide to try and breed them again.