The Big Bang Theory: 10 Worst Characters Who Appeared After Season One

Of all the people who belittled Leonard throughout his life, no one got under his skin more than his high-school bully, Jimmy Speckerman. Speckerman spent years tormenting Leonard by spiking his drinks with laxatives, stapling his scrotum, and shoving him inside a backpack. (How a teenager can fit in a backpack is anyone's guess.)

So, when Speckerman tracks him down years later to ask for his help, Leonard refuses on principle. Even though Speckerman made Leonard's life a living hell, you feel bad for him since he acknowledges his transgressions. After Leonard leaves, Speckerman tracks him down and apologies profusely for all his wrongdoings. In that moment, Leonard forgives him, and lets his former bully to sleep on the couch.

But as soon as Speckerman wakes up, he's completely forgotten about his heart-to-heart with Leonard the previous day. Not only that, he steals his food and starts calling him "Nancy" - a name Leonard despises. Realising that Speckerman has learned nothing, Leonard kicks him out of the apartment, as well as his life.

What makes Speckerman especially irritating is the fact that we absolutely believed he had become a better man until the episode's final minute. Only in that moment did we realise he was rotten to the core, and could never change.