definitley the salt and pepper.... to taste...
I generally undersalt my food.... I have noticed when eating at "home" that my mom tends to do the same... probably because my youngest brother and step-dad are salt fiends and will pile it one anyway. I think my taste is adjusted to this lack of salt. I rarely will shake salt over my food.
When I cook for other people I have to remember to salt more than I would like but sometimes I oversalt by accident
Your alfredo NEEDS salt but use caution and add to taste it is easy to go overboard and there is no return from the brink..... ovesalting is a good way to get kicked off your favorite cooking reality show
a sprinkle of coarse kosher salt and ground pepper along with some fresh parsley on top add a nice finishing touch to an alfredo IMHO