1. He met his best friend, Joel, in fifth grade. Their lives were near mirrors, right down to older siblings who seemed to be too good to be true (and got all the attention because of it). They've been almost literally inseparable ever since. Joel is the sort who's a natural at making friends, and Cliff, the quieter of the two, has always been happy to just go with the flow. Joel's friends are his friends, though he's never felt like he needed a large group surrounding him.
2. Cliff's older sister, Jess, was killed by a drunk driver when he had just turned thirteen, and she was eighteen. It was his parents' reaction to it and their inability to deal with it, coupled with his own grief, that drove him to act out. He lashed out at anyone who was convenient, started fights in school, and became sullen and angry rather than just quiet. This continued through high school.
3. Joel is the only person who can talk him down when he gets really angry. Otherwise, he has to have time to get control on his own. He thinks that Joel has probably saved his life on more than one occasion.
4. His mother committed suicide when Cliff was 21, shortly after Cliff began to seek professional therapy for his own issues. His mother's death drove his father to seek help as well, and they've patched together a decent relationship since then.
5. Cliff met his fiance, Leah, about 6 years ago. They had a very slow courtship, because he did not want to get in over his head and lose ground on the progress he'd made with correcting his issues. She was seemingly very understanding and allowed him to take his time. They were supposed to be married in June, but in April he caught her with another man. The aftermath was...well, bad. But he managed not to hurt, maim, or kill anyone. The wall in his apartment has seen better days, though.
6. As a surprise wedding present, Joel entered a radio contest for a week-long cruise to the Bahamas. He never expected to win it, but was planning to present the couple with it as a joke, followed by some more reasonable present. However, he did win it. He encouraged Cliff to go ahead and use the tickets ("maybe get laid anyway"). The two of them ended up taking the cruise together--bunking in the honeymoon suite, no less--and they had a great time. Cliff did not get laid on the trip.
7. His title at work is Technology Specialist. It might sound impressive, but only to those who don't know it's really 40 hours a week sitting on the phone with people who have absolutely no business even touching a computer, much less attempting to install new software or send an email. He absolutely hates it, but Cliff has never found that the idea of any career particularly inspired him, so it's better than having no job at all.
8. No matter what his high school principal might say about him, he's a genuinely good guy. He doesn't want to explode at people, and he always feels extraordinarily guilty when he comes down. It has taken years of therapy to manage the shame that comes with it.
9. Joel's daughter was born on Cliff's 31st birthday, and she is the reason he exists. He has no qualms about spoiling her, nor about seeming a little ridiculous to constantly go shopping the baby aisles for her. Joel and his wife, Amy, often joke that Cliff could care less about seeing them, so long as they bring the baby. They are his family, even if they aren't blood relatives.
10. He's a true pessimist, but he tries to hide it. He wants to see the silver lining; he just can't.