* administrativ rules that are impractible/impossible for (some) foreigners to be reasonably fullfilled (example: UA Mileage Plus asks me for transferring awards to do it in person with an UA agent - but there is none in Switzerland).
* little to no advanced info of upcoming rule changes (LH miles&more)
* bad wording (unsure rules, little training of employees) of promotions (example: StarAlliance promo: fly 5 and get 50'000 miles)
* 0 availability over a whole year of SQ first awards - I offered a flexibility of 365 days ... (tried with LH miles&more and UA Mileage Plus for ZRH-SIN and SIN-MEL)
* 'others' get comped status, for what I had to do it the 'hard' (flying/paying) way (US-carriers)