Let's say a scarf has 400 rows of 20 stitches each. That's 8,000 stitches. If you're a beginnner (like me), you're probably learning a new technique with each scarf. (My first scarf I learned how to just do a knit stitch. My second, I'm learning how to make stripes.) So it makes sense that by the time you get to your second 4,000 stitches, you will have figured out quite a bit about what works for you concerning your new technique. Who cares if you're not perfect from stitch one?
It's easy to think that if you struggle with your first row, you're going to struggle until the end of your project, so you better get that first row just right. But that's not true, and you'll drive yourself crazy and learn to hate knitting if you think that way.
Instead, remember that you're getting better -- and knitting is getting easier -- with every stitch. It's only supposed to be fun.