It's hugely variable. I've had the 15 minute experience too. Sometimes it feels like they're delivering trays forwards and then almost immediately collecting the trash backwards, although that might be too silly to be true.

The gap between special meals and regular meals can be very long in Y (special meals have easily finished long before regular meals are delivered), so those people in particular have a long wait with trays on their tables (and can't easily do anything about it because aisles are occupied with trolleys).

However, I think it's mostly unavoidable in Y, because of the sheer ratio of seats to CC/galleys. I often bring a small meal (nothing like a nice turkey sub), and some granola bars for later.