Yup, I think the one time I feel even a twinge of doubt is the moment of truth when you are meeting an approaching car(s) and know that there is also a bogey coming up fast on your rear as well. Do they see you? Is someone behind the car meeting you wanting to whip it out into your lane to pass? It may not be proper policy in the bigger bike-aware cities, but here in my area I just play it safe and try to pull off the shoulder as soon as this scenario presents itself. I live in an area where lanes are not only non-existent, they are UNHEARD of, and people just flat out are not looking for a cyclist. There's something that gets me in a rash...these same people are always worried about hitting a deer or the neighbor's dog (tho I wouldn't miss that nasty snarly/chasey yellow lab 4 miles away) but it never crosses their minds to watch out for US!! If you let it sink in and get to you-the fact that these lumbering tons of steel are hurtling past you only inches away-you would surely lose it