@Background Pony #EED2  
True

Also, Luna was banished a thousand years ago. It’s a long time between then and Sunset Shimmer.

@Background Pony #EED2  
You don’t have a choice, really. When someone betrays you, tries to kill you, then you can always be ready to accept them back if they repent, as Celestia was with those two - but if you stay hung up on the past, then you’ll miss the future.
 
She’s seen at least about 1000/25 = 40 generations of ponies. If you can’t move on when someone passes, then you’d soon be dead, yourself, in that position.

I think it’s awful of Celestia to constantly ditch her old “loved ones”
 
Luna banished - “oh well, I loved you but now you’re gone and I found this new girl who’ll admire me, at least I’ll be happy with her as my follower and I won’t feel the need to cry for your pain”  
Sunset banished - “oh well, I loved you but now you’re gone and I found this new girl who’ll admire me, at least I’ll be happy with her as my follower and I won’t feel the need to cry for your pain”  
Twilight - It’s just a matter of time (“for now I’ll hug you near Luna and Sunset and wonder if they get jealous”)