friendly and relaxed
convivial - friendly
Somebody or something ‘convivial’ is pleasantly cheerful and welcoming. This formal word was originally used to refer specifically to a feast with copious amounts of good food and drink but has since been adapted to describe any occasion, atmosphere, or person characterized by cordiality.
My concern that the meeting might become contentious ended up being unfounded. The atmosphere was convivial throughout.
We negotiated convivially with the other party at first, but when they began to engage in chicanery, we adopted a more hardline approach.
David’s conviviality is partly why he is so popular, but it also means that people sometimes take advantage of his good nature.