For as long as I've gone out to sit down restaurants, the payment process was: The waiter/waitress would leave the check on the table in a check book, then I'd put my credit card in the check book. The waiter/waitress would then come back, take the check book back to run the card, and return with the final check to sign off on. They would leave it on the table and walk away. I could then leave the tip and sign.
But now, hand held devices have intruded, and what I've experienced is the waitress will stick the card into the hand held in front of me, hand me the hand held, and stand there waiting.
No.
I am not going to let them brow beat me into leaving a larger tip.
The first time this happened to me I was caught off guard, but it happened again tonight so I told the waitress, "Can you come back?"
Then I discussed with my wife whether to leave 20% or 25%.
This made a formerly smooth and low stress situation awkward. To me this behavior is rude and intimidating. It puts a bad taste in my mouth. Stop hovering. Drop the hand held off like a final check to sign, and I'll leave the hand-held on the table.
I got used them when I traveled a lot (Italy, France, Spain, Portugal, the former Yugoslavia, and Australia and New Zealand) back in the '00s before the systems became popular here. And I generally turn the screen so the server isn't looking right at it when I choose the tip amount.