I know that my day always goes better when I say perek shira. Things usually go more smoothly for me on those days I say it. Not only that, my mood is different- calmer, happier somehow. My holy grandmother A”H requested I say it every day and gave me a bracha for each time I would.
And when I have those particularly hard days? It doesn’t last long like it used to and I also imagine things could have been much worse…. Hashem listens to our tefillos.