What is roff good for?

I was giving some thought to just what I'd gotten from a couple years of
fairly frequent visits to roff.

Thought I'd pass on the information.

(1) Encouragement to try a particular Idaho stream that I knew about, and
had seen, but had never fished ... thanks Russell
(2) Ott-Lite(s) ...I had never heard of them until rofft ... we have three
in the house now ... if you tie, buy one ( if you don't tie, start ...
nothing improves one's fly fishing as much as the information one gains as a
byproduct of tying )
(3) A modified rod grip that makes it comfortable to hold one's hand much
farther back than the "stock" version ... thanks Mike Connor
(4) Tippet rings ... just starting to experiment with these, but by using
Pitzen knots one can obtain very near 100% tippet strength as well as
several other big advantages ... thanks again Mike

That's it .... off hand I can't remember anything else I've found on roff
that has improved my fly fishing .... what specific things have others
learned here ? ( yeah, about fly fishing )