After a class that Susan taught on how to make bagged lunch to Greg, Rodrick and Frank, she started a shifting schedule on who will make Greg's lunch. When Rodrick made one, Rodrick wrote fake notes on the lunch bag, like "Dear Greg- Dont forget to change your diaper after fifth period. Love Mommy" and also once packed Greg a lemon as a fruit. Greg also never ate the sandwich Rodrick made as according to him, he has "never seen Rodrick washing his hands".
The Ugly Truth Version
In The Ugly Truth, Susan goes to study at college, so Frank, Greg, Rodrick, and Manny had to prepare the food themselves. Rodrick prepared Greg's lunchbag, and just like the online version, he wrote fake notes such as "Dear Greg, don't forget to change your diaper after lunch. Love, Mommy" and Greg wouldn't eat his sandwich as he thinks Rodrick has dirty hands and never washes them.