My girlfriend, like so many people, cannot visit the cinema without sandwiching her time in screen tightly between two visits to the toilets. I don't know what it is with other human beings and their inability to go one hundred and twenty minutes without a bathroom break - perhaps my bladder is just freakishly large, like some sort of urine-holding tardis. Either way, I often find myself waiting in the cinema lobby awaiting my girlfriend. In fact, so frequent an occurrence is this that I have invented a game to keep me busy in my accrued downtime. I call it 'The Escalator Game'. Funnily enough, the game itself actually manages to be less interesting than its name - I simply see how many times I can travel up and down the nearest escalators before my girlfriend emerges. I can't run, or even walk, up the stairs. I must simply stand. It's terribly exciting. My record is six.

Upon leaving a preview screening of Richard Curtis' new (and purportedly last) directorial effort, About Time, I found myself outside the ladies toilets in the Trocadero Cineworld. One of the two escalators was broken, and thus temporarily a staircase and ineligible for use in The Escalator Game. I was stuck in the depths of London's shittiest entertainment complex (I don't know if you've ever been to the Trocadero, but it makes the murky neon Los Angeles of Blade Runner look like the gleaming marble of classical Rome). The soundtrack to Mamma Mia was playing over tinny ceiling speakers. It was, curiously, the perfect place in which to properly evaluate the film I had just seen.

In many ways, About Time is the best film Richard Curtis has ever made. It is still burdened with the same sentimentality we saw in his previous directorial outings Love Actually and The Boat That Rocked, as well as his earlier writing credits for Four Weddings and Notting Hill. The film follows Domhnall Gleeson as Tim (a name that surely nowadays only exists in British comedies) who finds out, just after his twenty-first birthday, that the males of his family have the ability to jump back through time and change whatever they choose. The catch is that they can only jump back to points within their own existence, and that making the wrong choice can irrevocably alter the present.

To Curtis' credit, he avoids much of the butterfly effect that has weighed down other time travel films - though it still plays a large part in the path the plot takes. Initially Tim uses his powers to woo charming American Rachel McAdams, who here fills a part originally slated to be filled by Zooey Deschanel. If you feel that tells you everything you might need to know about the character, you'd be wrong - McAdams is, in many ways, the perfect movie girlfriend. She is kind, understanding, and always fun and interesting; she is also, however, anything but the cliché 'manic pixie dream girl'.

Later in the film Tim's attentions turn to his family - saving his freefalling sister, spending lost time with his father. But the plot feels secondary to the real heart of About Time. Much of the comedy is drawn out of Tim's ability to skip back and fix even the tiniest mistakes - the brief look in Gleeson's eyes before he announces that he needs to pop away for just a second, and the anticipation of how he might fix his fumblings. Despite this, the heart of the movie is found not in the time-travelling, or the rather slight plot, but in the characters. Particular note goes to Tim's delightful family, who are realised rather lovingly. Tim's mother is affectionate and stately - but peculiarly down to earth, too. His disastrous sister is equally lovable, despite being on a constant mission of self-destruction.

The battle for best performance comes down to one of two actors. Bill Nighy is superb, as ever, playing essentially the same character he always plays in Richard Curtis films - but injecting it with a vulnerability we always knew he was capable of but have not previously had the chance to see. Tom Hollander, on the other hand, steals the show somewhat (particularly in the first act) with his fantastic train-wreck of a playwright. Bitter, sweary and a little bit pathetic, Hollander is terrific and, most importantly, laugh-out-loud hilarious in his time onscreen.

There are, of course, weaknesses. Tellingly, they are precisely the same as in every other Curtis film. The sentimentality is almost draining at points, aimed squarely at the sort of women who are a little too old for Nicholas Sparks; the sort of men who don't like war films but still want grand, noble and sacrificial gestures. There is, as ever, a closing montage. Of course there is. And, inexcusably, Curtis insists on having one incomprehensibly stupid character. I have no idea why he is so committed to this trope of his own creation. Notting Hill had Rhys Ifans. Love Actually had Kris Marshall. The Boat That Rocked was made up of so many of these characters it had to specify the one Curtis had put in there on purpose by calling him 'Thick Kevin'. It's a tiresome source of tiresome gags, and here Richard Cordery has the thankless task that the film would doubtless be much better without.

It's noticable from the start of About Time that the best moments in Tim's life always play out without his time-travelling intervention - his initial meeting with McAdams' Mary; a brilliantly conceived wedding that, despite disastrous weather and a lot of competition is easily the best across Curtis' works. This is, in part, the big statement of the film - making the most of every day, enjoying the little accidents that make things so fun. Standing still and enjoying the beauty of every moment.

And so we return to me, standing at the bottom of the broken escalator post-film, listening to Pierce Brosnan murder Abba through cheap speakers. It's an ugly scene in almost every way, but fresh out of the cinema I find myself seeing the beauty of the situation. The stillness of the broken stairs next to the quiet motion of the down escalator beside it. The way Brosnan's vocals only serve to emphasise the tattiness of the cinema itself. And for a minute I find myself wondering if Richard Curtis might just have succeeded in teaching me a lesson about life itself, and the importance of finding joy in even the smallest of things. And then I remember that I'm the man who invented The Escalator Game, and he was probably just preaching to the choir all along.