an alternative idea?!

Drugs and alcohol don't really loosen you up. They just depress or stimulate your nervous system enough for you to not care and be more willing to do or say things that you wouldn't normally do.

You're asking for a safe alternative that provides that same result, but there's nothing. You say that you don't want social interactions as an answer, but that's the best you'll get. It's not the same sensation, but being in healthy social environments that you feel safe and secure in is the best thing you can do to loosen up and feel natural.

EDIT: As a side note, I realized that adrenaline CAN be a good alternative. Really exciting activities and sports such as snowboarding and surfing will often make the desire to become intoxicated seem pointless.

An actual way to loosen up and feel free is - Meditation. Nothing else. Just nothing else at all.
Prove "that someone" wrong by practicing it and I am sure if you've asked this question then you can do this as well.
It's a practical approach. You can feel free when you don't have any barriers on yourself. You'll feel free when there is no one who can restrict you for anything. You'll feel free when you dont want anything........... and all of this comes with the real practice of Meditation.
Do it and prove him/her wrong.

Wish you success
Dr Rudra

http://www.rudraayurveda.com/

Jon is right.

alcohol and drugs doesn't make u loosen up...it just makes u to lose ur interest..not care..and do anything..I myself have been going under severe depression and the only things that helped me not to care are Marijuana and alcohol..which gives me a little time to be less abnormal when Im in a party or around people in order not to bring them down as well..but my situation is different
no person with a healthy mental state is dumb enough to these to show someone else that their wrong.
i believe meditation is bullshit...never done a thing for me..boring and makes me think more..and i get anxious more than before..!
i suggest you guys use ur inner spirit to loosen up..and thats by not givin a sht and trying to have fun..
dont try to poke ur adrenaline level by doing dangerous stuff..it can coz serious problems
if none of it helped or none of the other answers..
just tell that someone that they were right..! there is nothing wrong with admitting that

Personal experience and web searches