Other days an interruption costs me pretty much nothing.
I’m still trying to figure out how to tell which of those days I’m going to have and whether to just not log into Slack for the day.
What specifically makes it painful for you?
I dunno. I've just always felt much less productive with someone else there. I don't view programming as a social or collaborative activity. Building software can be collaborative, but when I'm sitting down to do implementation, collaboration slows me down, and I find it very frustrating and unproductive.
Sharing an office where you can’t look at each others screen unless you walk over to help troubleshoot or design a specific feature is probably my favorite mode of work by far. Especially if it’s a small hyper-competent team with a diverse set of expertise but basic generalist knowledge to navigate the entire design at a high level.
Being able to jump on a whiteboard with zero latency mid-debugging session (even trying to move to a spare conference room) is also great.
This also lets you devise team communication in a way where you can signal you are in focus mode vs not and others can gauge the importance of their ask based on that signal and knowing precisely what everyone is actually working on that day.
That said, the absolute worst possible way to collaborate is video conferencing and shared screens. Give me a shoulder hoverer over that any day.