When great spirits clash, sparks fly about. [ French Proverb ]

Great interests are apt to clash with each other. [ Lucan ]

Custom is the law of one description of fools, and fashion of another; but the two parties often clash - for precedent is the legislator of the first, and novelty of the last. Custom, therefore, looks to things that are past, and fashion to things that are present. [ Colton ]

Society is but the contest of a thousand little opposite interests - an eternal contest between all the vanities that clash with each other, wounded, humiliated the one by the other, and which expiate tomorrow in the disgust of a defeat the triumph of today. To live in solitude, to avoid being crushed in the surging throng, is what the world calls being a nonentity - to have no existence. Poor, miserable humanity! [ Chamfort ]

Consistent characters are those which in social intercourse are easy, sure, and gentle. We do not clash with them, and they are never wanting nor contradictory to themselves; their stability incites confidence, their frankness induces self-surrendering openness. We feel at ease with them, we are not offended at their superiority, doubtless we admire them less, but we also hardly dream of feeling envious of them, and they seem almost to disdain malignity by the peaceful influence of their presence. [ Degerando ]