Pause etiquette

Hi Reddit,

What is generally considered good pause etiquette? In the game I played just now, my opponent paused in mid-castle age and didn't say anything (not even a number taunt). After a while of still being paused, I sent a message, and got no response. How long is "good etiquette" to wait, with no message or reason for pausing? I know I have the ability to unpause on him, but I don't wanna do that in case there is some real life emergency going on. However he was keeping me waiting suspensefully for a long time.

Eventually, after about 15-20 minutes (not sure exactly how long) he just unpaused the game - again, no messages or taunts.

I don't wanna be the kind of guy who denies pauses everywhere, (leaves me feeling annoyed if I'm not allowed to pause the game for 10 seconds...), but I also don't want to be waiting 'in the dark' for an opponent who I didn't even know if s/he had any intention of coming back (I was ahead in the game).

Thanks in advance for reading and commenting :)