That's curious, because I would classify Brahms as the exact opposite kind of composer: he is always at his best. (And indeed, he was a ferocious self-critic, discarding far more music than he published. Essentially none of the discards survive.)

But there's another side to this: Brahms is also one of the few composers whom many people with demonstratably good taste loathe. Although I've found that if you enquire further, they usually say, "Except for this piece, and that one, and this other one," and on until they show that they like more Brahms than they hate.