"Tch... it's no good... When I ride a Bike in the tall grass, nobody can see my coolness."
- Cyclist on Route 119, Omega Ruby & Alpha Sapphire
I don't blame him, because that tall grass really did conceal him, or at least what I think it finally did in 6th Gen, because I felt like that the very tall grass didn't look very tall in most previous generations, with Sinnoh's Route 210/214 in D/P/Pt probably looking the least tall. I do remember this same NPC's quote was different in the original R/S/E, because back then you couldn't ride your bike in the tall grass or in fact, prior to 4th Gen, even run in it. And 6th Gen makes bikes now have this weird magic power to ride through the very tall grass that once blocked them.
Random NPCs always have weird and hilarious quotes, but as Pendra said the Doctors and Nurses in 5th Gen really were the most notable ones, like the one Doctor in Unova's Victory Road who said he wanted to see bad shape Pokemon in battle. And don't get me started on the Hex Maniacs and Fairy Tale Girls in 6th Gen... they say such creepy quotes.
... and don't forget that Psychic on Route 10 in Kalos who mentions your Pokemon's power levels are "over 9,000", as a reference to the famous term from Dragon Ball Z.