In the lab, after Lisa and Bob (and Homer) finished the marshmallows, Lisa tried some Pomato juice, and she liked it very much.
"Have you ever made an actual pomato?" Lisa asked. "Not just the juice?"
"Indeed I have," Bob said. "The skin has the sweet juiciness of a tomato, but the inside has the delicious center of a potato. Unfortunately, I don't happen to have a pomato with me, but perhaps I will the next time you visit."
"This is so exciting!" Lisa squealed with a big grin on her little face. "It's going to be so much healthier than Dad's tomacco plants!"
"Tomacco?" Bob repeated, raising his eyebrow in curiosity.
The smile on Lisa's face became more strained and embarrassed.
"It's a long story," she said, "involving my dad's ill-conceived attempt to live as a farmer." Lisa looked sadly at the pomato in her hand. "Look at me, getting all enthusiastic over a hybrid vegetable. I guess it's a bit weird."
"There's no need to get embarrassed," Bob reassured her. "You're not becoming enthusiastic over a mere vegetable, you're becoming enthusiastic over the advancement of science and its benefits for humanity. More people ought to be like you. You're like a little lighthouse on a barren island, shining your light over a cold, apathetic sea."
Lisa grinned again. She liked praise from anyone; Bob could recognize that the child's self-esteem was rather delicate, and considering her family, he was not very surprised about that. Making a child smile felt nicer than making a child scream in terror.