During one of my later lessons we planned to route through Luton's zone. Whilst on frequency and waiting our turn we listened to another pilot making the request. His R/T was non standard and he gave a very vague route - the ATCO asked several times for clarification of his intended route - and when he failed to get a satisfactory answer he gave an exhasperated sounding "G-xx, you are NOT cleared through the zone, remain outside controlled airspace."
We quietly gave up our plan and routed around his zone.
I guess that's a little more then "fluffing your lines" but it did seem that sounding competent could make the difference.
Ali