If she dashes to the door with the car keys in her hand, she's probably just not that into you. If she sits down with you and pauses for a moment, you're looking at Russian superstition rearing its head. It's traditional to sit in silence for a minute or so before embarking on a journey.
It was believed that allowing yourself a moment's pause to put your thoughts in order would trick any bad domestic spirits into believing you were not actually leaving. Therefore, only good spirits would accompany you on your trip and you would have good fortune. It's an obscure explanation that most Russians won't have heard before. In modern times, this little practice is just a nice way of clearing your mind from the madness of cramming too many things into a minute suitcase. It's also a chance to try to remember anything that might have been forgotten. Sit down politely and focus on the present. Did you pack lunch? Are the passports in your bag or still on the counter?
Russians have a bit of a thing about leaving on trips and forgetting things. It's hard enough getting yourself organized, let alone your friends/spouse/charming but forgetful children. But in Russia it can be even more of a headache. Returning to the house, just like leaving it, means you're upsetting the bad house spirits. If it's not super important, it's best to just go without. However, if it's a plane ticket or your child's favorite toy, you can dash back so long as you head to a mirror and stare yourself in the eye. Some say you should smile but that seems a little creepy. Either way, this little trick should quiet the pesky house spirits and allow you to carry on your trip, free from supernatural meddling.