Why do straws have those red and sometimes yellow lines on them?

Straw manufacturers noticed that straws with stripes sell better.

That's why they have straws and stripes forever..

I had a friend that was a floor manager for a straw manufacturing facility.

Lots of companies color code straws for various reason. Most common being the date they were created. They will have very specific codes for the month/year that the straw was formed. For example, McDonalds runs 4 major batches of straws White with yellow lines, White with red lines, white with both yellow and red lines and white with blue lines.

Actually, I just made that up, bad dang if that doesn't sound feasible though, huh?

one of your finest posts McG. And I've been reading your stuff for 8 years

Actually, all straws become twisted after repeated use. The straight ones become twisted and you can tell when the lines reveal the degree of twist. Likewise, straws that are produced with twisted appear to have straight lines when the seem to "untwist". If you are given either straight or twisted straws, complain long and loud till they replace them. If they don't, threaten to report them to the county health department.

I liked it too - one of those thumbs is mine.

Very through the looking glass! Yours is the straw that broke the camel's back.

P(h)UNNY

It's purely for aesthetics.

tres clever

That makes a lot of sense, other than I don't feel compelled to buy stripy straws(maybe some people are subconsciously?). Thank you for answering an insanely random question!