Notice who’s happy for you when it doesn’t benefit them.

Gladness that costs the other person something is the rare kind. Plenty of people can be pleased for you when your win raises them too, and the real test is the friend who is genuinely delighted when you get the place they wanted. That reaction cannot be faked well, and it tells you most of what you need.

Watch for it, and keep those people close rather than convenient. Then try being one: when somebody you know gets the thing, say so properly and without the small cold sentence afterwards. It is harder than it sounds, and it is the difference between a friend and a rival.