@Marluxiana & Black_Wing_Angel
Don't forget the time component. Preparing a real salad from scratch takes a lot of time and effort, which you can't afford when you're running between your 3 jobs, not to mention the time you have to spend shopping for it because lettuce gets gross in less than a week.
Personally, as a poor/starving student with variable time constraints, almost all my meals consist of rice, lentils, and frozen veggies with whatever seasoning I feel like. But even that takes more time and effort than, say, a microwaved TV dinner. And part of the reason I like it is because I was raised on healthy food - hamburger helper makes me feel sick (actually, most foods with a lot of raw glutamate do that). If you learn instead to go for those highly-preserved foods, healthy food will taste weird.
http://www.cracked.com/blog/the-5-stupidest-habits-you-develop-growing-up-poor/
I'm glad to hear that you're healthy, black_wing_angel, but you're an exception, not the rule.