Friendly troll Justin is best Justin.
Susan's not a regular player of this game, and is playing it for reasons other than the game itself. Because of that, I knew from the beginning that she would not be the architect of her own deck.
What I wasn't certain of from the beginning was who was going to help her build a deck. I considered both Justin and Tensaided, and one reason I chose Tensaided was to further the friendship of Susan and Tensaided.
As evidenced by Susan not buying Justin's phony dismay for even a second, Susan's affinity levels with Justin are already quite high. Undoubtedly, Susan already has access to his companion perk, and... Wait.
Sorry, I forgot this wasn't Fallout 4 for a second there.
Anyway, given their closeness, I wanted to address why Susan wound up getting help from Tensaided.