Had the very untenable position a few months back where we were inbound to ZRH on a Sunday night, dark but reasonable wx and told to hold at Ekrit, delay not determined.
Fuel situation was OK as were tanking fuel in so the 40 minute hold (as it turned out) was do-able, but on investigation the reason was due to ATC trying to launch 18 aircraft off 32 and so all inbound aircraft had to hold. As an ex-controller this is a ludicrous example of setting priorities, as the airport was empty when we arrived so there shouldn't have been a problem with stand allocation. There were several diversions.
I notice BA have linked up with Swiss to use the 'major hub' of Zurich. Laugh, I nearly bought a round...