I bought my first sewing machine last summer and haven't used it too much. I was trying to learn from the manual, which is difficult, and I had the hardest time sewing in a straight line for the little purse I made.
I hadn't used the machine at all since coming back to the US, so I took it over to my friend's house for a sewing lesson over the weekend. The reason it was so hard to sew a straight line? I had never put the foot down! So the fabric was just going every which way, guided only by my hand.
Now it's a lot easier to sew straight :)