A couple instances come to mind.
1) Don’t have sex 6 hours after you delivered a baby.
2) Coffee creamer is not the same as infant formula. Please do not feed your day old newborn International Delight.
3) Probiotics are different from antibiotics. Probiotics do not cure syphilis.
Patient had been referred to my pharmacy by his physician for an OTC enema. The guy was not the sharpest tack, and apparently either his physician did not explain it well or the guy didn’t listen, but our conversation went like this:
Pt.: So I drink down this whole bottle and then I’ll hafta shit?
Me: No sir, this is an enema. It is used rectally.
Pt. (confused): So what’s that mean, I don’t hafta drink the whole thing?
Me: No sir, you’ll lie on your side and insert the applicator tip of the bottle into your rectum and squeeze the contents into you bowel. You’ll then remain lying on your side and hold the enema in until you feel the urge to have a bowel movement.
Pt.: You tellin’ me I gotta stick it up my ass!?
Me: Yes sir, this is an enema and it is used rectally. There are detailed instructions and diagrams in the box.
Pt.: FUCK YOU!
And he stormed off. That was the last I saw of him. Not sure if he thought I was messing with him or what, but I hope he eventually got to shit.