I just got back from the PagerDuty Toronto office, where we have a large part of our engineering division.
I had a few meetings scheduled ahead of time, and an idea of who I needed to see, but almost nothing about the visit was on the critical path for a given project... and yet it was probably one of the most productive and useful weeks of work this year.
I had coffee, broke bread, drank beer, and played Magic: the Gathering with 20-odd teammates from the other side of the continent, each of us fleshing each others' Slack handles into full-fledged human beings, with their own hopes, dreams, challenges, and fears. An hour or two at dinner highlighted some communication issues that had somehow never come up in months of working together remotely, and we all left the week reinvigorated about our work and our team.
Chat, Google Hangouts, and JIRA make distributed teams possible, but there is no substitute for real, live physical facetime. It doesn't have to be frequent, it doesn't have to be every project, but I believe it's absolutely critical for teams to perform at the top of their game.