Quality of Service
Software is a product. At the same time it is a service. For one, it is the service providing executable machine code for algorithms, which might even be free accessible knowledge. In addition, it is the service to maintain this machine code, meaning both, removing errors and adapting to changing environments.
Especially the last is a reoccurring issue with open source software. I am not opposing open source software, far from it. But, really, get your act together! Have some ambitions and strife for high quality of your open source software; especially when talking of non-functional aspects like usability and quality of service. The usual excuse “but it is for free” reduce the whole concept to absurdity.