When you're thirsty in a movie theatre and you forgot to smuggle in a beverage, you're often forced to buy water at the theatre. More than likely, it's the Coca-Cola water, Dasani, which tastes like absolute crap and has salt added to it. But you muddle through...
The Bourne Ultimatum was good, but I think it was the weakest of three Bourne films. The plot wasn't very strong, and there were some characters and issues still left hanging. I thought the final resolution of Bourne's identity quest was too neat, too easy, and too anti-climactic. (Maybe it's based on the book, which I haven't read...)
David Strathairn was great as a cold, calculating CIA higher-up; Julia Stiles was kind of blah as an agent "coincidentally" popping up wherever Bourne is (they never go anywhere with that. Why have the coincidence if it's not going to be developed more, except as a catalyst for a manhunt in Morocco?)
However, the action sequences and vehicle chases made up for all the plot and character mediocrity. There were some amazingly well-choreographed fight scenes and cool car/motorcycle chases through half a dozen cities.