This. Its not really friendship (although sometimes it does turn into that too!) but a human connections. Understanding that the people that you’re working with are humans with hobbies, families and other interests makes it much more enjoyable to work with them. This is especially true for highly creative fields like Software Design. You’re also likely to create connections with people you may not work closely with (eg from Sales, from another team etc) that can lead to a better understanding of different perspectives of the company/product.