It is hard to think of a "worst" but sometimes the ATC in Zürich is very arrogant. Additionally, there are problems regarding departures and arrivals in ZRH
at certain times which create huge delays for no good reason. Why ZRH
has just 2 ILS approaches and just 3 total approaches is beyond me. ZRH
can be a real pain in the A$$. But it can also be not too bad.
Some of the nicer airports are:
(Charles de Gaulle, Paris) - works well despite its huge size.
(Berlin, Tempelhof) - Classic feel, right in the middle of the city. Time machine atmosphere. You feel as if you should see some DC-4s and 3s on approach and rolling around. Cool Airport.
(Florence, Italy) - Beautiful approach.
(Bern, Switzerland) - Friendly ATC, nice small atmosphere
(Madrid, Spain) - Giant airport. One of the last places in Europe to see "Classic" airliners like 727s and DC-8s in action.
(London City) - Approach to 10 right over downtown London. Steep approach. London ATC is VERY busy, but works smoothly.
But the best is LUG
(Lugano, Switzerland) - 6.65° IGS, spectacular mountains all around, special certification required, spectacular visual approaches. This has been my home base for 2 years. As a pilot you will learn more there in 1 week than a year of flying 3° ILS approaches in the rest of Europe.
If I think of more I will post them.