I think if you are stressing about little things, and/or causing more stress in your life, you are doing it wrong. If you miss a workout, it's your fault, you could have worked out at 5am or moved a day off around. You should be able to out to dinner with your grandparents, order a plain chicken breast and rice, and call it good. Doing these things and making these adjustments should cause you zero stress. It's not about just sticking to the diet and workouts, it's about doing it all stress free. I think people like to make a big deal about how "dedicated" they are, when really they are just adding unnecessary stress to their life. Stress is probably worse than missing a workout or having a cheat meal.