The new kid on day one is nervous, not boring. Wait until they relax.

Nerves flatten people. On a first day almost everybody becomes a quieter, more careful version of themselves, giving short answers and laughing slightly late, and none of that is their personality. Judge them there and you have met their anxiety rather than them. It usually takes a couple of weeks for the actual person to come back online.

Be the one who makes the relaxing happen faster. Ask a low pressure question, save them a seat, pull them into one inside joke. You will meet somebody you would otherwise have written off by Friday.