What does an appreciable negative effect on competition mean?

Throughout the years, much intellectual energy has been invested into drawing the line between being anti-competitive by object or by effect, ignoring that an
infringement must also be appreciable. Most likely based on a presumption that this is no longer a separate requirement, but part of analysing the former. However,
case law does not render full support for this, thus making it necessary to revisit the issue of being appreciable as a potential separate requirement.