If nothing excites you in this world, then I think you should start looking for one. If you live without believing that tomorrow will be better than both today and yesterday, then I think you should start changing something.
We were very used to this feeling of excitement as children, but as we started growing older, it's more about responsibilities and less about activities that fill us with joy or excitement, and I accept that as a part of being a grown up, but, this is something you need.
After multiple years of searching tirelessly for my passion, I've discovered that I'm so passionate about languages in general, and the English language especially. I'm always passionate about learning new things and sharing it with people, and I believe it helps.
I'm also currently studying German, aiming to get to the B2 level in German, and this is again something that fills my life with joy and hope that tomorrow is better because I can easily get better job opportunities given the fact that I speak 3 languages.
That's why I believe that, again, you need to always have something you're deeply interested in and passionate about, something that fills your life with joy and makes you excited about tomorrow. Most importantly, makes you feel that tomorrow is better than both today and yesterday!
Hope this was helpful in any way!