Friendship is Relative
Violet: I like him.
Mary: You like every boy.
Violet: What's wrong with that?
It's a Wonderful Life
In places like Sweden, folks are more reserved and less "friendly" than in the U.S. When reserved and friendly cultures meet, the reserved folks often say they were initially fooled into thinking others liked them in particular. It took time to realize that their acting "friendly" did not actually indicate that they were more likely end up being friends in deeper ways. Eventually they learned to gauge how much foreigners from that friendly culture like them by comparing how those foreigners treat them, relative to how they treat others. Friendliness, as a signal of deeper interest and loyalty, is relative.
The movie quote above describes a common insight, that some people are "too easy" as friends. But salesman, politicians, etc. seem to usually act extra friendly to everyone; do we discount them enough for their being too easily "friendly"?
Expressions, how close they stand , do they look you in the eye, do you feel the vibes..... If politicians smile all the time at everyone I would say not trust them and that has been proven right.
There will also always be people who will pretend to be your friend cause they want something from you. A ride, money, your husband. You have to have good senses to figure it out.