For me, the motivation comes by having other people use and respond to the software I create. This means getting out of my developer bubble and doing some marketing. When people are engaging with your creations in a positive way, it's hard to not be motivated.
I think this applies to any software product that is written with the intention of having someone else use it, open source or otherwise.
I think this applies to any software product that is written with the intention of having someone else use it, open source or otherwise.