Hold off on initialing the worksheet
Being asked to initial the worksheet is a small yes that makes the bigger yes feel already decided.
At some point, the salesperson may slide the worksheet over and ask you to initial a number, or sign at the bottom, so they can take it to their manager. It's framed as a formality, just to show you're serious.
The worksheet isn't the contract. What the initials do is create a feeling of commitment. Once your pen has touched a number, walking away feels like going back on your word, even though nothing has been agreed. And when the sheet comes back with a counteroffer, you're negotiating from a number you already initialed, often a monthly payment rather than a price.
People like to stay consistent with what they've already said yes to. A small yes makes the next, bigger yes easier. That's ordinary human nature, and the process happens to fit it well.
You can be friendly and still decline. Something like: "I'm happy to wait while you check with your manager, but I'll hold off on initialing anything until the final paperwork." If they need something to take back, you can tell them your out-the-door number out loud. Your number doesn't need your initials.
When the final paperwork arrives, read it line by line against your deal sheet: price, fees, add-ons, APR, term and amount financed. If anything differs from what you agreed, that's the moment to stop and ask. Your walk line still applies, right up to the last signature.