I remember this bit of the actual show and PB looked like she could cry and Finn knew that, but he was torn between Flame Princess and PB, but he thought PB would break his heart again and he couldn't go through that again
Sherlock Quote from 4x01 │ Sherlock Holmes (to Rosamund): As ever, Watson, you see but do not observe. To you, the world remains an impenetrable mystery, whereas, to me, it is an open book. Hard logic versus romantic whimsy – that is your choice. You fail to connect actions to their consequences. Now, for the last time, if you want to keep the rattle, do not throw the rattle.