That's the shitty part about living in a unit complex - you don't know who's above or below you and there's not much buffer if they're merkins.
Before we bought our house, the missus and I rented a brand new unit in nth parramatta... It was really nice, close to church street food strip, close to everything really. We loved it.... Until... Until a group of early 20-somethings moved in directly below us. They were typical of that age group I suppose, but the smoke from the cigarettes and bongs wafting up past our balcony and bedroom window became too much. We were 4th floor, they were 3rd... And then when you looked over the balcony to the garden bed on the ground floor, you could see where they were throwing empty bottles and cans etc... We were lucky enough to know that it was short term, but I always thought, imagine if you had bought one of these brand new units to live in, and they were really f**king nice units, a pool in the complex and all, but imagine you spent all that money intending to live there for good and then you're surrounded by rentals occupied by f**king trash tossing merkins and Bob Marley and the Wailers living underneath you!! You'd be livid....