This isn't the Obi-Wan quote you're looking for, move along.

"Only Imperial Stormtroopers could be so precise."

Excuse me?! This right here should've been where Luke's Force-Sensitivity kicked in and he began to question Old Ben's intelligence. Granted, Obi-Wan had been detached from most galactic affairs for close to twenty years, what, with his self-imposed watch over Luke and all, but still... Even the Clone Troopers had poor aim! Seriously, come on, the only time a Stormtrooper hit anyone of importance was on Endor when that one winged Leia, and that most likely happened on accident while he tried suppressing a sneeze! (That Stormtrooper who shot Leia on the Tantive IV doesn't count because he shot her with his E-11 set on "stun")
Did Obi-Wan's mind deteriorate that badly though, while in his hut those sleepless nights without Qui-Gon, or did he leave Tatooine for a little bit to raid the secret stashes over in the spice mines of Kessel and that's what gave him such delusions? Whatever the case may be I have to say that my faith in Obi-Wan has now been shaken after discovering this piece of misinformation in Episode IV. Maybe Owen Lars was right when he said that Obi-Wan was "just a crazy old man." And we all thought it was Yoda who was crazy!

(Come to think of it, all the Jedi Luke encounters after he first finds R2-D2 and C-3PO are a little out there. Maybe they all decided to drop acid after the fall of the Republic. An interesting theory, must investigate further...)