I usually eat a big bowl of salad for lunch, when I am working from the office. If I eat a big meal, I get bloated and tired (TBH, not as nice as my normal self).
I bring a bowl, and a chopping board and veggies from home and carry it around everyday, just to make it fresh. When I came across this idea, it inspired me to pre-cut my salad and bring it in a jar. I don't carry around a lot of equipment and more importantly- it is sealed and fresh.
One of my favourites is a Nicoise Salad. A salad from Nice (France), traditionally made out of tomatoes, lettuce, hard-boiled egg, Niçoise olives and tuna, dressed with olive oil and mustard (I add caesar salad dressing).