Is it difficult or time consuming?

I think that it sort of draws a parallel with Ted/his wives and Angel/Darla-Buffy.  

There's clearly a parallel between Angel and Ted in general--they both are lurking in Buffy's room, looking at her stuff when she sneaks in through the window; they're both the monstrous, older (neither of whom seem nearly as old as they are) boyfriend.  And Angel sort of makes a case for Ted--encouraging Buffy to give him a chance despite her misgivings, her distrust of Ted's perfection.  And there's a weird boyfriend/daddy conflation going on--where Ted refers to himself as "daddy" to Joyce, treats Buffy like a father would immediately after meeting her, but Angel is similarly counseling not as a friend or boyfriend, but as an elder with wisdom--as a parent.  

But, when Ted's true nature and past relationships are revealed, they bare an eerie resemblance to Angel's:  The main relationship of Angel's life was, of course, Darla.  But, like Ted's wife, Darla left Angel--rejected him.  And he, in turn, destroyed her.  But then, like Ted, he pursued a woman who fit Darla's bill to a T--petite, blond, saucy. Angel recreates his mate with Buffy, then, just as he did with Darla, he destroys her.  Or tries to.   

Xander perhaps says it best:

So, I'm Ted, the sickly loser. I'm dying and my wife dumps me.
I build a better Ted. He brings her back, holds her hostage in his
bunker'o'love until she dies. And then he keeps bringing her back, over
and over. Now, now that's creepy on a level I hardly knew existed.