With standard whole peeled canned tomatoes, I agree on the seeds.. I've actually attempted to remove the seeds on a few occasions.
but with the D.O.P. San Marzano, there are actually very few seeds so the blender works perfectly to make a good pizza sauce consistency. They are literally in the blender for 5-8 seconds so I don't think it has time to have any noticeable negative effect.
The San Marzano tomatoes are generally sweeter and less acidic. No need for sugar with them (or any sauce I make).
Phil makes a good point on the red pepper flakes as it relates to the "mood calling for it".. Just becuase we all do something one way most of the time, doesn't mean it has to be all of the time.. A little variation from time to time makes it interesting and fun with a good foundation/base.
Lonestar 24" Vertical offset w/ Insulated Firebox & Performer Platinum
Former owner: Jambo Backyard, Klose BYC, Med. Spicewine, Pitts & Spitts, XL & (2) Med. BGE's, 22" WSM & (2) 18" WSM's, 18" & 22" Weber Kettles