Muffin is not a biscuit. It's not a cake. It's not quite breakfast fodder. It's this weird cakey thing that you grab when on the go, when hungry but it's not lunchtime and the only place around is a Starbucks with their stodgy oversized and overpriced blueb or choc things. Having eaten one of the S ones especially, you feel bloaty and stuffed instead of pleasantly sated.
I used to consider muffins an inferior product. No skill in the making, not much fun in the eating. I still don't rate them very high but make them occasionally as it's so quick and easy: dry mix, wet mix, bish bash and done.
Buttermilk is a good ingredient as it gives a lighter texture. Brown sugar instead of white works well and makes the muffins less sickly. Use oil instead of butter and you can pretend it makes them less calorific*. But the genius ingredient is frozen fruit - you mix it into the dry ingredients and it won't dissolve into pink mush. Finally add some white chocolate chips and so get what I would call a half-respectable product.
*it doesn't. Butter and vegetable oil pretty much the same in terms of calorie content.