Hard to say.
Quality is hard to determine seeing as it's very individual, but there are always songs that are a bit "odd" in a band's catalog, but the band-members love themselves.
When it comes to new albums I'd say the artists have no chance at judging their music, X amount of years after they release an album, they will look back at it with some criticism, but when they made it, it was the best thing ever.
So in terms of new songs and albums, the artists will always say "this is the best thing we've done" pretty much, and it's great that they have confidence, but it's way too early to tell.
Otherwise I think it's hard to say, an artist might dislike a song that everyone likes, because they have some personal experience related to recording or writing the song, which will sorta "taint" it forever.