Yes, I think it was unrealistic dialogue.

Being the CEO, he doesn't know about all the little technical stuff that everyone does in his company. He wanted Peter Sullivan to simplify the situation as much as possible. It wasn't a very realistic line. I don't think a real CEO would say that exactly, but something like it isn't farfetched. I'm sure it was meant to be amusing to the audience for the most part.

I was talking about when Jeremy Irons character asks them to explain the problem as if they were talking to a golden retriever.

My take on that was:

1. When Spacey was crying at the beginning, the audience, and Will, may have thought Spacey was upset over so many people losing their jobs, when in fact, he was crying about his dog (for himself).
2. The dog represented the part of Spacey that was human and caring, something he clearly left at home when he went to the office.
3. The dog represented a loving life that he left behind for greed. He apparently took his dog with him when he left, although at the end Spacey admits that the dog belonged at the family home.
4. At the end he's digging a hole, flashing back to the remark he made when Irons said that Spacey could've been a ditch digger, and Spacey responds that if he had been a ditch digger, he'd at least have some holes to show for it. But in fact, despite making tons of money, he can't leave his job because, as he said, "I need the money."
   What I got out of it was that Spacey hadn't realized what was really important. He could've had it allmoney and a loving family (remember when he admitted that he hadn't thought to tell his son about the big problem coming down, despite his son working in the business?) and a devoted dog. But he chose instead to go after the big bucks and a cutthroat existence, disregarding everything else. He doesn't even care that people who worked for him for years lost their jobs and would lose their homes.

No, still don't get it.

Purely in terms of general everyday facial expressions they are not the smartest looking of creatures.