Joke: So I was donating at the Red Cross one day...
This is a true story, I'm a frequent platelet donor
An assistant walked over to check on the machines and everything, after a quick inspection, he look toward me
Assistant: Everything feeling okay?
Me: Absolutely not!
Assistant: What's wrong, is there anything I can help with?
Me: Well you see I've been stabbed and I'm bleeding!
Assistant: Oh my God! Where were you stabbed?
I gesture towards my left arm, he looks at the needle stuck in my vein, and the tubes running into the machine, filled with blood. And he groans and walks away.