I want to talk about Giles leaving in season six, and why it bothers me so much. There are a lot of reasons, so I’ll just go through them.
Buffy, generally speaking, isn’t a normal person with exclusively normal person problems. People’s lives literally depend on her health, mental and physical.
That, to me, is just part of what makes Giles’ abandonment of the Scoobies in season six so awful.
Just to recap, in Tabula Rasa (6x08, the episode Giles leaves in) Buffy is:
Regularly (i.e.: constantly) putting her life and wellbeing at risk at an unpaid job (all the financial stuff of this season is for another post)
Financially and emotionally supporting her unstable teenage sister and herself after the sudden death of their mother not a year ago.
Lacking in a stable adult figure outside Giles
Surrounded by friends dealing with issues and instabilities of their own
Clinically depressed and suicidal (referring to her failed attempt in Once More With Feeling here)
It’s not like Giles doesn’t know all this when he decides to leave. He watches Buffy attempt suicide and announce to her friends how much pain she’s in, and apparently just chooses to ignore it.
Maybe now’s not the best time to be teaching Buffy a lesson about being a self sufficient adult.
No way does any sane person look at Buffy’s situation and go, “You know what she really needs right now? The only stable adult/parental figure in her life to indefinitely and without warning leave the country!” The whole thing just feels very out-of-character for Giles.
Buffy is a complete mess at this point and he knows it. And when she needs him most, he bails. Way to show some adult responsibility, Giles.
Giles staying and offering some form of support may have significantly helped Buffy in finding healthier ways to cope with her situation and eventually heal a little. And in spite of this, later on, his leaving isn’t even addressed as a huge mistake for which he is 100% responsible, so much as just a neutral thing that happened.
I’m not saying the writers shouldn’t have written him off for the season. It was pretty much necessary to all the character and plot arcs, and I think Anthony Head left to spend time with his family anyway. I’m just saying I wish they’d chosen a less sucky way to do it.
My suggestion would probably have been something along the lines of creating some urgent yet vague Watchers Council thing for him to attend all season. If done well enough, I think this could actually work as good setup/continuity for The First in season 7.
That said, season six is one of my favorite seasons despite all its flaws, and this is definitely one of the bigger ones.