cascade-issue.scss

%relative { position: relative; }
%absolute { position: absolute; }

.something { @extend %absolute; }
.something-else { @extend %relative; }

// Given an html element with class .something and class .something-else
// The cascade will resolve to position absolute instead of position relative as you'd expect.
// This is because the position aspect of these classes is not an essential inheritance relationship.
// It is simply composition -- so only mixins should be used.