Just had the honor of playing with a Challenger
And he was by far one of the most toxic players I have ever played with. I'm sure that there are some other challenger/master/diamond players out there who are nice and are helpful. But he just left top lane to rot and left the mid lane to defend against an Azir who was constantly pushing.
Not to mention he was a total dick to the entire team and refused to cooperate and group once the surrender vote failed. If the attitude of most challengers is like this, then boy am I glad to be gold.