Despite multiple coats and letting the stain sink in as long as (or even
sometimes longer than) recommended on the can, my stain never seems to
get nearly as dark as shown on the can or as shown in the store samples.

- I have found this both with multiple different Minwax oil stains and
with Rockler gel stains. The stain never gets nearly as dark, dense,
rich as shonw in the samples.

- For me this is true both for pine and (red) oak -- which are the types
of wood shown for example in the Minwax samples.

- It happens both on unsanded S4S wood and on wood sanded to 200 grit

- Also it happens whether or not I use a pre-stain wood conditioner.

- Finally it happens even with multiple coates (4+), even when using
very generous applications, even when kept on longer than recommended,
and even if I don't wipe it off aggresively at the end.

The only areas that stain as dark as (or darker than) the samples are
end grain.

What could I possibly be doing wrong?