Part of it is they probably don't remember what it's like to be a kid about to get a shot. But also they kind of have to do whatever they can to convince the children to let them give them the shot.
When they lie to kids, the next time that happens the kids won't be as willing to do it. Each time they say that, next time it convinces the kids less and less.
I talked to three children, my grandfather, and a doctor. The experiences of the children whose doctors didn't lie to them, they felt ok. But the children who did get lied to by their doctors and nurses didn't like it and it just made them feel worse. The doctor said:
Myself, as a doctor, and the medical assistants I work with, say it will hurt but just for a minute, or it will feel like a bee sting. If you ever choose to be a healthcare provider, the recommendation is not to lie to your patients. You could talk to your doctor and ask them not to lie to you. When they lie it doesn't help: everyone knows shots hurt!
My grandfather said:
When I was about three I had an operation to take out my tonsils. I asked the doctor if it would hurt, and they said yes. I said "that is a true man!"When I asked one of the children whose doctor does lie to them how it feels, they said:
Bad, because they are lying to me. Because it does hurt!
I think they should say that even though it will hurt a little bit, the kids can be brave and it will be all right.