Example a suite of genes. Such as a set including genes for: blond hair, straight hair, blue eyes, fair skin, prominent nose.
If you had this suite of genes, you would be very poorly adapted for an equitorial environment.
You would suffer more sunburns, heat stroke, skin cancer, cataracts, and vitamin D poisoning than a neighbor who's darker skin filtered out more UV, whose curly hair acted as a better parasol, whose flat nose didn't stick out into the sun as much, whose iris did a better job of shielding his eyes lenses from excess sunlight.
Even if you lived long enough to pass on your genes, you would probably die sooner, before you had a change to pass on all the accumulated wisdom you had gained. Some critical information would have a higher chance of getting lost, such as which spring survives seven years of drought, so your kids die, because their suite of genes was disadvantaged.
Does this make any sense to you, or is thinking it through too much of a stretch for you?...