I don't mind when people drop by to discuss things. I may take a small productivity hit in the short term, but I gain a lot of insight into what others are working on, and get a chance to point someone in the right direction before they file a PR that I then have to review and ask them to re-implement things in a different way, which is way more frustrating than just having a quick in-person conversation.

The added friction of having someone jump on a call vs sending a slack message and stopping by my desk has resulted in a lot more tedious PR reviews where you end up having to explain your approach with a wall of text and then still having to jump on a call and re-explain the same things in more depth.