Gaming the system - it doesn't work
Every criminal defense lawyer has had clients who think they know more than anyone else, and refuse to acknowledge reality. For reasons I can't explain, they are usually the clients who are obviously guilty - and there is no defense. There are multiple eyewitnesses, or physical evidence, a confession, or some combination thereof. In those case, the only question is generally how much time are they going to do.
Your first hint that there might be a problem is when you convey what you believe is a reasonable offer, and the client responds with "I can't do that much time". Logic would say that if you can't do that much time, you certainly can't do more, but they never seem to grasp that. Instead, they seem to believe that the prosecutor really cares what they think. I have no idea where this comes from. In some cases, the person has always gotten what they wanted, and they assume it will be the same here. Others just don't think the same way everyone else does. Mark Bennett recently commented on this, noting that there are some people you simply can't reason with.
The client who knows better than you is frustrating for many reasons. Most importantly for me is that their case almost always ends badly. I want to do the best for each client, and I take it personally when they end up with more time than they should. You always wonder if there was something you could have done differently.
I'm writing about this because I just finished another one of these cases. It had been dragging on for a long time, and has been set for trial several times. Each time the offer went up - you can't blame the prosecutor, because they had a great case. In the end, the client recognized he didn't really want to go to trial - maybe he knew that deep down all along. By the time he made that decision though, all the offers were off the table. Basically, he negotiated himself a worse deal - when it should be the other way around. Unfortunately it's not the first time I've seen that, and I'm sure it won't be the last.
I'm not sure there is answer for this, or a best way to handle. Maybe there are some people who you can't reason with. If anyone has the answer, I would love to hear it.