[RGlasel]

The fastest lens I own is an SMC A 50 f1.7 that was the kit lens on a Program Plus I bought used 12 years ago. I was experimenting for my own benefit, so not everything is the same in each picture, but I think these pictures illustrate the effect of aperture on the overall look of a photograph fairly well.
f1.7

f4.0


Now with the wooden vase and candle at the same distance from the camera
f1.7


f4.0 (for some reason, this image was overexposed and I can't PP away the flare)



f5.6


f8


f2.8

It seems to me that the best results are between f2.8 and f5.6, where you get blurry backgrounds that don't distract from the main elements, but more than a single element is clear enough to look natural.

[hks_kansei]

Bear in mind that there are more factors than just the aperture in effect here.

the subject distance to the camera has an effect, as does the background Distance.
And of course, the distance from the subject to the background also has an effect.


I usually just make a point of learning roughly the depth of field each setting gets me (scale on the lens) and using that.
Of if i'm using a camera with DOF preview I cheat and use that instead :P