depends on how badly you want the job determines whetheryou should be pissed or not...
Things come up and people get busy, meetings run late... unpredictable things happen... sucks for you... but you want something from them...
The question you should ask yourself -- are you pissed enough to not want to work for the company? If it bugs you enough that you're questioning whether you should be pissed or not - why do you want to work for them?