Is this amcl pose with covariance good? I barely added any parameters. How can I make my attempt more challenging?

edit

The above seems to be good. The ellipse/circle remains small and the arrow doesn't show too large a range.

But the weird part is that I didn't add any parameters to the amcl node.

So the default parameter values do such a good job?

What can I do to challenge my robot simulation such that I can tune different parameter values and gradually observe the results?

I don't like that I get good results without doing much work here.