Friendly, describes people who are kind, caring, and make you feel comfortable. You might be new to town, but the people are so friendly that you'll soon feel right at home.
The noun friend is at the root of the adjective friendly. When you're friendly, you treat everyone like a friend — with warmth and respect. A friendly game of badminton is by definition not too serious or competitive, and a vegetarian-friendly menu makes non meat-eaters feel welcome, just as user-friendly instructions make it easy for non-professionals to follow the directions.