Like a doggie in a window, this romcom relentlessly wags its tail so you’ll fall in love and take it home. Not this time, puppy. There’s nothing terribly wrong with About Time, it’s just that it rarely rises to its potential. After all, director Richard Curtis is the go-to guy for writing fluff with feeling (see Four Wedding and a Funeral, Notting Hill and the Bill Nighy parts of Love Actually). But Curtis keeps About Time on simmer for over two hours, losing focus and letting its appeal run off as vapor. Here’s the plot. Goofy, lanky, ginger-haired Tim (Domhnall Gleeson) gets a surprise on his 21st birthday. His dad (Nighy, splendid as usual) tells him the men in the family can act like Bill Murray in the far-superior Groundhog Day, meaning they can go back in time and repeat any day from their past. Nothing too serious, mind you. As dad says, “You can’t kill Hitler or shag Joan of Arc.” For Tim, it’s a chance to perfect his first date with Mary (Rachel McAdams, way underused). What happens next results in such mild surprise that I won’t spoil it for you. But the point is we should enjoy each day as it comes, no manipulation. Why then tease us with time travel for a fortune-cookie life lesson? The actors have charm, but not enough to compensate. The fabled Curtis touch, light and fluid, deserts him this time. Dragged down by whimsy and sentiment, About Time feels like it weighs a ton.