From time to time, some may suggest an idea on the mailing lists or in the IRC channel, and get an answer of "Patches Welcome". While this may seem rude or unhelpful, it's mean to summarise a range of different responses to suggestions of changes to programs, the OpenStreetMap web site or some other technical aspect of the project.
What does it mean?
"Patches Welcome" is shorthand for "No-one has the time to work on this. If you'd like to see it done, you'll need to do the work yourself". Everyone working on OpenStreetMap, including developers, is a volunteer. This means that they will work on what problems interest them most or that they think are most important, since that's the reward they get.
Even people whose job involves working with OpenStreetMap and its data have an obligation first and foremost to their employer, not the OSM community. Even if their employer allows them time to work on core OSM software they're going to fix the bits that mean most to their business, not the community. Sometimes the two will be the same thing, sometimes not.
Don't take it personally
Getting an answer of "Patches Welcome" doesn't necessarily mean your idea is a bad one. It definitely doesn't mean that it's just because it's your idea. Often, the idea will have been suggested before and received a similar response. It's not meant as a brush-off, but a shorthand explanation of a complex situation.