Heat the olive oil with the garlic over very low heat in a small skillet . When the garlic turns opaque, add the chili flakes, salt, and squeeze the lemon into the oil. Turn off the heat--the garlic should gently begin to brown around the edges. When the oil has cooled somewhat, add the parsley so that it gently wilts. In the meantime, cook the spaghetti in abundant, salty water until al dente. Drain, transfer to a serving bowl, then cover with the warm oil and toss with tongs. Drizzle more olive oil if desired.
