Buffy

This is a sort of deabte esq issue, but i didnt figure it was good enough for GD and MPSIMS is about as general as you get so…
What is the deal with Vampires and entrances in Buffy, and Angel? Occasionally there is a big deal made about going through a doorway but on numerous occasions Angel, generally, ends up bursting through a window (The episode where Angels premonitory friends ex-wife is going to marry another half demon) or being mysteriously within a dwelling (the very first episode of Angel). I am being pedantic, but i like being pedantic.
I realise that many times Angel can enter a building because it is not actually a humans home, but im sure there are errors.
Actually, I just kind of want a general Buffy thread and this seamed like a good pretext. I am in Oz and i think we are probably a season behind you USAliens, so no blabbing plot twists or I will undermine your economy.