I must respectfully disagree. Yes, anyone would be pissed, and yes, it was just a cup...but it's just plain despicable behavior to respond by yelling profanities and throwing *anything*.
You might consider that whoever took his parking spot was not necessarily some entrepeneuring jacka$$ who thought, "Hey, there's that guy waiting for this spot. Let me just go and steal it from him." He may have been, or it may have been a misunderstanding - we don't know. That part isn't all that important.
What's upsetting is that a guy as high-profile as Sam reacted the way he did. You don't respond to rudeness by descending to their level, and you keep your composure in check. For someone who's supposedly destined to lead us on the road to glory in '07, that was low-class behavior unbecoming of a leader.
Don't get me wrong - I'm reserving judgment on Keller until I see him play and what he does for us on the team, and I'd love to see things work out on both ends. But when something like this happens, we've got to acknowledge it's wrong. No point defending what amounts to basically indefensible behavior for a guy who wants to be the pride of cornhusker nation. I like the guy, have high hopes for him, but I'm not happy with this bit of news.
Besides, we're talking about a Keller throw

Very likely it tore a hole through the midsection of the car and ground to a stop sixty yards later.