I Also headcanon that Extra Life never got love or given a hug so if someone hugs him out of the blue (like how Amy hugged Shadow in SA2 for example) he would tense at the unexpected embrace. He would be in confusion and surprise. He clearly won't be used to physical contact, and he definitely didn't like being hugged, He was not accustomed to such things as hugs and affection. The idea of accepting love was completely foreign to him.
Extra Life: "W-What are you doing, you idiot? Get off of me! Let go of me, before I-" *He threatened, struggling to get out of your hug*
I like this headcanon. It makes sense given his backstory, while trapped in the box he wouldn't have gotten the chance to receive love. Even before he got trapped It also seems that Kintobor was never all that nice to him, given that he apparently seemed to view Extra life as just a glorified servant for Sonic.