A Question of Service?

Restaurants have such a small window of opportunity in which to impress a customer as the diner is only there for an hour or so. 
One could argue that serving a meal is such an interactive process that things can go wrong in a heartbeat and are more likely to than not.  Having said that, why is it that many restaurants can’t get it right even when they are nigh on empty? 
And why is it that hospitality often fails to impress when sometimes just a smile and some eye contact with the guest would put everything right?
Is it attitude or is it lack of training? or both?

Something to ponder on!