go against the grain

MomoはSalvatoreが家に帰って来るのを何時間も待ちました。深夜になりMomoは戸の前の階段で寝てしまいましたがやっと帰って来たSalvatoreの話を聴くことができました。
'I've been talking rubbish,' he said sadly. "I'm drunk again, Momo, that's the trouble. I often get drunk these days, there's no denying it, but that's the only way I can stomach the thought of what we're doing over there. To an honest brick-layer like me, it goes against the grain. Too little cement and too much sand, if you know what that means.
今日は上に出てきた "go against the grain" を覚えたいと思います。
・Cambridge Idioms Dictionary: if something that you say or do goes against the grain, you do not like saying or doing it and it is not what you would usually say or do It goes against the grain for William to admit that he's wrong. I don't think she likes to praise men. It goes against the grain.
・Wiktionary: To defy convention; to do something in a manner that is unusual or out of the ordinary. His method certainly goes against the grain, but it is unquestionably effective.
・American Heritage Dictionary: To go contrary to someone's natural disposition: “Having to get up this early in the morning really goes against my grain.”
This refers to the fact that someone who rubs his hand against the grain on a piece of lumber will get splinters.
最後に引用した辞書の説明が分かり易くて良いですね。