Do only advantageous mutations fuel evolution?

Advantageous mutations have been demonstrated to exist. The fact that most are disadvantageous is a moot point as they die off leaving the status quo. Only the beneficial changes that are few and far between result in the dramatic changes to the landscape. This explains stretches of apparent stasis followed by rapid change. My understanding of it anyhow..

That which survives in an environment is beneficial by definition. That which perishes in an environment is deleterious by definition.
When you go shopping you pick the best fruits and vegetables available to purchase.
It is all relative to what else is around to compete.
I might be able to kick snot on an elementary school kid(deleterious) but be placed in my casket by Mike Tyson(beneficial).
Again as I understand it.

That would be because shalamabobbi doesn't know that much about it yet. Thanks for all the great input. This site has been very helpful and sets a very high standard. Not all of us are unappreciative of the time spent here by busy scientists. I alas am a lowly engineer but the choice was sort of a toss up for me.