I recall an incident while I studied Spanish. An older woman in my class was nearly in tears of frustration as she angrily demanded of our teacher why they use "estar" to denote locations. For example "París está en Francia". Given the naive classification of estar as temporary it seems counter-intuitive to suggest Paris is temporarily in France.

There are a few other ambiguous ser/estar situations we were taught, exceptions to the permanent/temporary distinction that I can't recall. But the near break-down this woman had about Paris was quite memorable.