there is a reason why lemon-grab is so angry. it is because lemon-grab was no normal lemon person because he was not only artificial but also princess bubblegum used a personality core called "cave" this personality core was in fact cave Johnson right before he died. he was downloaded in to the lemony body he got mad because if there is one thing he hates,it is lemons. that is the reason why lemon-grab is so angry all the time.