More than any other relationship strategy, goal, approach, a culture of helpers is key to sustaining teamwork.
The terminology of a helper I actually borrow from Adam Grant with his eye opening TEDtalk in which he asks: Are you a giver or a taker? This is not to say I was blindly convinced by a thirteen minute video on the merits of helper cultures, rather my various work experiences support and confirm his conclusions.
As a manager at McDonald's for example, one of the most valuable expressions I learned was Be Here Now, which is to say: Don't lose sight of your current customers and your current team. Business comes from people—customers and coworkers—so take care of them first.
In addition to this, as I've worked a few other places since then I've seen firsthand the practical value in assuming innocence by default, not to mention making sure to say thank you when your team helps you out. Otherwise, attitudes and behaviours of mistrust or lack of recognition tend to change peoples expecations of the team environment—ultimately weakening a culture of helpers.
Create and maintain an environment that supports a helper culture, and you'll have a strong healthy team: Morale is just as important to a team environment as the product being made.