I have visited Mostar last weekend, and one of the reasons to visit the 'Croatian side' (political divide is a very complicated matter in BiH, as many people would know) is the existance of HP Mostar, one of three companies responsible for postal service in Bosnia and Herzegovina (other two being BH Pošta and Pošte Srpske).
I have checked their stamp issues online and knew instantly I was in trouble - soooo many great stamps! Alas when I arrived to the main PO the philately desk was closed, and it was only thanks to the enormous friendliness and help of the ladies working at other desks that I have managed to find some different issues (I wasn't able to go through the whole catalogue, I am especially sad for not getting a donkey stamp as I even had a donkey postcard to attach it to, but it was my own fault for not remembering the year of issue!), the result being this lovely cover with local flora (endemic to the area) - Helleborus hercegovinus and Lilium martagon var. cattaniae (2014).
Hopefully there will be more visits in the future, as I loved Mostar and its spirit!
Btw sshh but I have to say, I prefer their issues to the ones of my own country ;)