Well to tell you the truth... because I'm afraid of cardio. Like genuinely. Two of my family "men" have died after effort... one came with his bike home and had a vein pop out in his head at 25 years old or so after effort. Another one died after he got home on his bike, was kind of tired, and the elevator was broken so he used the stairs to get home (at the 8th floor of the building) and his heart stopped and started vomiting and coughing up blood and pink foam (sign of pulmonary edema) - and he died basically of a heart attack after effort.
So I keep that in mind and whenever my heart rate goes up at pretty much anything, these things keep coming up in my head and I get scared and my heart rate goes even higher and my fatigue increases a lot in just a few seconds. Then I'm done.
That sucks, man! But cardio doesn't necessarily have to feel like "effort" to be worthwhile. In fact, sometimes it should be really easy. You could just take a brisk walk around your neighborhood, or go hiking somewhere, or something like that. Don't think about it as focused exercise, don't
try to get your heart rate up, just get out and move around a little bit.