So many in ATC appear not to appreciate the inter relationship between speed and descent initiation. Recently told that the F260 constraint would apply at Sonny. Descent delayed due to traffic crossing below. Had passed planned top of descent so started to slow down. ATC come back with "CXXXX are you slowing down", "Affirm (otherwise will be unable to make constraint)". ATC reply with a very curt "maintain speed". I understand that we need to maintain common speeds for separation, but a thinking man in the above situation can see that a slow down pre descent followed by high speed in descent will sort out the requirement to make the constraint and maintain separation.
On a similar vein, do ATC realise how much easier it is for us to cope with speed requirements in the descent if those speeds are given prior to the descent point? Any speed changes in the descent are inefficient, and use more fuel.