Worst nuisance people had to deal with during the Middle Ages?

Hard question depend on which century and in which social class through Medieval era climate was wamer and due to many advantages ina griculture and early industrail revolution (or as some historians say medieval industrail revolution) most of harvest were good and profitable, due to demographic and economic boom popualnce rose high so i would say that worst nuisance was that in any region and in any century there was moment when sistuation led to overpopualnce and that would made an economci and social rpoblems which led to migration, other would be a plague in some area but we must remeber that during medieval era there was only one pandemic on continental and global sclae balck death which killed mroe than a third of European popualtion