Friends hi-fi system not very good, what do you do or say?

I probe with questions:  "Are you happy with the bass level you have? " Depending on the answer, you can either offer advice or just STFU. 

I would probably say, I'm trying to find a diffuser panel aesthetically pleasing and nice looking and doesn't look like everybody else's since they're all buying it from the same place. Something custom would be cool if I could find something I like to look at.  And then the problem is it has to be larger and take up a fair amount of Wall space to achieve any effective results further complicating finding something that looks good.  Of course if you have a lot of furniture in the room probably achieves the same damn thing.

I onced had a former work-mate. I helped him out on a job he simply could not complete. So he asked me to dinner at his home, with his wife. My eyes naturally turned to the T.V. where I discovered his "stereo" was located beneath it. It was an all in one system, an AMSTRAD with the speakers bunched tightly together. Just like as illustrated in the catalogue. I asked him how he played L.P.s as there was no room for the lid to open. He immediately got down on his knees to show me his "stereo". and enthusiastically poked buttons and got the VU meters to work. But did not play any music.

I invited him and his dog, to my home to cook him a meal in return. It was a trap. Before he started to tell me the plot of a drama he watched on T.V. (this is his idea of conversation). I switched my humble system on and loaded the Eagles, One Of These Nights, into the disc tray, tilted the balance to 11 o'clock to put him in the sweet spot. He exclaimed that he thought seperates were not made anymore.

His dog dashed back and fore, ears pricked to see where the sound was coming from. He just sat there silently for 2 minutes, then started to tell me all about a TV drama he had watched.

Eagles speak louder than words. Yes, I became an audio snob that day. There is no reason to comment on the sounds, Just sit back and let the music play.

I haven't heard anybody else's system for years so I have no idea what anybody elses system sounds like.  I just have my imagination to work with.

So this was all just a theoretical question?

"I invited him and his dog, to my home to cook him a meal in return."

You invited him and his dog, but not his wife?! Interesting dynamic.