After the first kiss, all thoughts of going back were abandoned. They decided to eat at the pub, and spent the evening talking about everything and anything: pets they'd had when children, their favourite things to eat, their families - his mad mother, her dodgy brother - favourite films, bands, books. Everything Bertram said Arabella thought was incredibly interesting, and by the time they were walking home hand in hand she was half way to being in love.
In other words, the conversation would have very dull to anyone who wasn't involved, readers included, but we needed to know they enjoyed that first evening together talking about inconsequential stuff. As you do on the first date with someone you like.
Try this exercise. The situation is an interrogation. It goes on for at least ten hours (could be longer) and at the end the interrogated person finally lets slip some useful information.
Write the scene in a maximum of 20 words. Then try 100, then 250. Which is easier?