I usually bring it or buy it there coz it costs less and I don't care who sees me eat or if I don't have someone to talk to during lunch. Lunch is meant to be eaten, not to get cold on a plate while I'm yapping.
I bring my own lunch. I actually did some calculations and found out that I saved up to $2,000/year just by bringing my own lunch! So yeah, my main reason is to save money!
I try to bring lunch everyday to work it saves me a lot of money, they have a cafeteria here at work but its not very good and they are pricey! Its about $8.00 for a meal, if you average it out to a year it will about about $2000.00 a year!!!