Yep, that's what I meant. I guess the test of the value of something is how or if it affects someone who isn't interested in the subject ... as with blind tests etc.
We might be able to judge better but we might also be able to influence the decision or be interested in a particular outcome (especially if we may have risked some of our hard-earned on it).
Like when I changed the front suspension rubbers for poly-bushes, the road springs and dampers I really wanted it all to be better ... but no matter how I tried to persuade myself, it really wasn't (isn't). My experiences we also in direct contrast with many who had done the same thing and they ALL said it was 'much better'. Maybe they wanted something different from their vehicles?
If I do stuff on the Mrs car / motorbike / cycle I generally don't tell her and see if she notices. ;-)
Cheers, T i m