EK leave
Another favorite... the "manual insertion" turnaround in between your leave and a block of days off... if you even get a block.
Or the ever used ULR flight after leave which means unless you're going somewhere nearby you need to be acclimatised for your duty and that means being back at Base a certain time before duty which eats into those "days off" because they're used as a way to make you legal... shifty rostering and shouldn't happen but they bank on people not complaining about it.
It is a little different between CC and FD but I have seen this on both kinds of rosters and it can really fk with your leave plans especially if your leave is a week or less... ergo... take as long blocks as you can or they will screw you with a late finish before and a ULR after...