One of new junior devs after his 3 month "trial period" was good enough to keep him so he went to boss to talk about his future.

He came back with big smile and told us how much of big raise he got (now earning as much as seniors)

I asked my boss what was so special about him, maybe we should improve somehow, he answered "He was yelling at me, what could I do?"

Now I know how to approach him next time I talk about a raise :p