I think bumping into each other is a cliche, especially when it comes to a couple who will become romantic partners, I see it frequently in romance films and it does irritate me. Plus it tells me nothing about the character really other than they are clumsy or so caught up in their own business they don't pay attention. Neither are traits that are interesting to me. Try doing some research on the "characteristic moment". It's a way to introduce a character in an interesting way that illustrates the important things you need to know immediately.