I appreciate few people here are likely to do this, but nonetheless I feel it needs to be said.
If you find out that the person you meet at a party is a member of a healthcare profession, do not respond with "Oooh... does that mean you have access to prescription drugs? Could you get some for me?" Most healthcare workers have invested significant time, money, energy and emotions into gaining the qualifications for their job and their work while on the job. These have probably been a large sacrifice for them to make. It is unlikely that they will be willing to risk their livelihood to oblige you in acquiring prescription medications. You may think this sort of question is funny, but they probably won't. You're unlikely to seriously ask a bank worker to steal you a roll of bank notes, so why ask healthcare staff if they'll steal dangerous prescription meds for you?
Unless the location you are meeting in is rather noisy, it is not polite to stand very close to a person you have just met. Some people like more personal space than you do, and intruding on their space may make them uncomfortable. Read the visual clues you're getting from them- if they're repeatedly backing away you probably need to move back a bit.