Livre d'Or

This was my experience too - though in some ways having a few serious health incidents to break the thing up might have saved me from being too messed up by the work itself.

I think possibly one of the worst sides of it was that after two or three years in a "normal" job I didn't like (but hadn't failed utterly at), I could've happily found another job with no consequent black marks on CV; whereas the sunk-cost thing with a PhD means that dropping out early does Not Look Good career-wise (assuming one wants to carry on in the same field), and one can't readily continue in PhDdom with a different choice of employer.