When an employee asks you a question, you will feel like you don't want to be abrupt and will find yourself taking a few minutes each time.
I find a lot of the time employees will come with questions they could have asked over slack/chat that would have not broken my flow, and could be resolved quickly with a link, etc.
Its much better to develop a consensus on how to best use productivity tools asynchronously, and optimise your flow.
E.g.
- Instead of walking over - ask on slack first. - If something is less urgent, link to Trello card/Github issue/etc. with more details.
On Slack, using the right channels/rooms is important too. Serendipity and collaboration from overheard conversations is really really important. Physically overhearing discussions that you could weigh in on can save huge amounts of time and catch problems early on, but can be a distraction. In flow/with headphones you lose this ability to overhear. Having public chat rooms you can monitor regularly is the best. Avoiding employees private messaging each other is the goal.