There are usually a couple of times a week when I will compare my google analytics result often I will have a difference in 1-3 clicks. In my example - I will have a total of 16 visits for the day, but analytics will say that 14 of them are from adwords and 2 are direct/bookmarks.. Is this an error in the tracking bug or is there some reason that Google is charging me for clicks that they aren't generating from my adwords account?
clicks and visits aren't an apples to apples comparison. you can(and will often have) times where you show more clicks than visits, since a click can happen multiple times from the same visitor, etc..as this is the case, you'll see a variance, usually between 5-10%, between analytics and adwords. both are correct, just different methodologies.