Software development is one of the most intensely collaborative processes I know. But stereotypically, programming is often seen as an activity for loners.
The majority of collaboration between developers is hidden because it happens across months and years. When I write code, I am working incredibly closely both with the original architect and with the future employee who hasn't graduated yet. I am communicating with people I may never meet, but also to past and future versions of myself.
When I leave work, most of the collaboration that I have participated in that day hasn't even happened yet.