I've always been a big fan of communal meals, lunch included. That way, you can coordinate to avoid conflicts (or the same thing) for lunch and dinner, lighten the overall load on the group by including it in the meal plan (instead of everyone planning all their own lunches, bringing all their own condiments, etc.). And it's just more fun to be with everyone else having lunch. ...except for that one grumpy guy that somehow got invited and sits off alone on his boat scowling at everyone else while eating his PB&J.
Also, I've concluded that wraps are far better than sandwiches for minimizing microtrash.
Nothing in the world is more yielding and gentle than water. Yet it has no equal for conquering the resistant and tough. The flexible can overcome the unbending; the soft can overcome the hard. - Lao Tse