I bring mine, dine in my office, and tune out for a bit.
Eventually, I will get burned out and go the local establishment.
No no no - you're not allowed to do that, because you might answer the phone, look at an email, move some paper around on your desk. Can't have that! You'd be 'working' and then be entitled to sue your employer for overtime.
When I got reimbursed for lunches, I’d grab something and drive over to a quiet park and read. When I didn’t get reimbursed and there was a cafeteria, I’d bring a sack lunch from home and read in the office.
Kind of the same thing I do. Sometimes just to get out I will take my lunch to my Dads business and eat lunch with him and visit.
First day on my new job and I eat my brown-bagged lunch at the cafeteria with the guys. Half way through, a user (I was a programmer) comes over and starts discussing the project I am doing for him. I tell him I'll get back to him after lunch and later got some crappola from my boss for "not working with people".
I drove a camper then, so at lunch time I just repaired there and ate in peace and silence. The rest of 'em thought I was anti-social.
[Distantly related]: A young guy I worked with came by one time, all agog that he was invited to a "Power Lunch" where they would discuss some outstanding problems. I told him that the company was "letting" him work through his lunch hour. Deer in headlights.