In residency, I once watched an attending performing urodynamics on a patient.
The attending did a rectal exam on the patient, and after it was over, he didn't change his gloves. So he was using the same glove, smeared with poo and lube to touch other things, including the computer monitor.
When he smeared poo and lube all over the computer screen, I nearly lost it.
And then at the end of the procedure, he patted me on the shoulder with that same hand (thankfully, he had removed the glove, but not washed up). I had to go sterilize myself after.