Let’s get a list started.
I’ll begin:
“Why would I buy another whistle? I already have one!”
intresting idea：
“which whistle is more better？”
Things Whistle Players Never Say?
How about:
“The bombarde is the only musical instrument that’s both a noun and a verb” 
“The bombarde is the only musical instrument that’s both a noun and a verb”
… unless it’s a trumpet 
Back on topic … “Why should a whistle need tweaking?”
Back off topic:
OR a whistle.
OR drum. OR harp. Or flute, fiddle, accordion, bugle, horn, chime, block, or pipe.
I just had to try and get this over with, although I’m sure I’ve missed something. Now back to your regularly scheduled program.
“Honey this is the last whistle i’ll buy!”
..although thinking about it, that is exactly what your typical whistle player will say 
Ah finally - I’ve found the perfect whistle !
Actually that’s what i often say when i try my latest purchase
No argument. Emily plays congas and bodhran. And sings.
“I’ll pay for this round.”
What’s a whistle? Did you mean pennywhistle?
Why yes, it is just like a recorder.
The jig is up! No, reely, now put that in your hornpipe and smoke it. 
Cayden
“All whistles are the same”
“It’s similar to a real instrument, but less challenging.”
“I play too fast!”
What’s that you say dear: Its you or my whistle collection?
well of course I’ll get rid of the whistles
.
.
I’d actually say this one, but odds are the hearer wouldn’t realise he’d just been insulted.
less challenging? sometimes less IS more… yes CT, that is funny
It’s called a “flutey thing”.