If it's friends/family, usually it's in your favour

but it raises some interesting (maybe) points so apologies for the long post.
I've always believed that whether a song is 'good' depends as much on the listener (& their place & time) as the music itself, so it will always be difficult to judge before releasing something.
I've found if you play one of your songs to a friend/relative and they know it's one of yours, they will listen to it with different expectations than if they heard a commercial song for the first time. Typically with yours, they'll offer suggestions to improve it, like adding more bass, emphasising the vocals, re-arranging parts etc. But if they hear a song they don't like but subconsciously know is finished, as with a commercial song, they'll say things like "it'll grow on me" (especially if they're a fan of the artist anyway)... and usually repetitive playing makes a lot of things more likeable. I've often wondered if I told them the song was from an album by someone else (i.e. implying it's a fait accompli), would their comments be different?
I think a lot of it also depends on being in the right place at the right time; look at the popularity of some covers where they've stripped back the production to the bare minimum - one that springs to mind is Mad World. I don't know for sure but I wouldn't be surprised if the original demo was similar to this, but electronics was all the rage then so it was 'enhanced' into a synth-orientated song - still great mind you

... but years later someone strips it back and comes up with a truly haunting version, and yet it's the same song!
So it all seems to be tied up with psychology and the listener's memories/perceptions.
I've never been impressed with my songs - they've been sat in 'demo' form for decades, but I accidentally played one the other day (it was in a collection of misc music on random shuffle), and my first thought was "that sounds pretty good, wonder who did it?"... and then realise - doh!