Not so hidden passion

Sometimes if I am eating alone at home, to save time, I have my meals at the small wall-side table in my kitchen next to the window, instead of in the dining hall. From my kitchen window, there is a condominium next to my house. I can see the lifts along the corridors.

It was during those eat-alone sessions, quite a few times, I happened to see a couple at the corridor. The guy looked like a tall man with dark features, while the girl was fair with long hair. I could not see them clearly of course. The couple would chit chat there for a long time, hug, touch and cuddle with each other, and of course, often accompanied by a few long and short kisses. However they did not do anything further than that. :P

I am not saying they are doing anything wrong but I am quite surprised and wonder why they would do it in full view of everyone who is staying opposite.  And a bigger question mark is.... I am befuddled why they did not do whatever they were doing inside the comfort of their own apartment, and why outside along the corridor next to the lifts. More kick??