"It's okay, I don't eat a lot."

It's not even a lie! Madoka certainly feels like she wouldn't be able to take care of an entire basket by herself anyway. So why not share? Especially if poor Sam is missing out on the picnicking experience otherwise.. that would be such a bummer to her.

"Besides, it's a lot more fun to have a picnic together with someone else, instead of sitting around all alone."