Questions after checking/tasting a batch in primary

I popped open a batch of American amber (based on the Brewer's Best kit) that's been in primary for 6 days to see how it's doing. I have a couple questions from that:

My hydrometer kept sticking to the side of my wine thief. Any tips on how to get it to stay centered?

The aftertaste is very pleasant, but the first note I got when I tasted it was cheap wine. What usually causes that? (Greenness? ) I'm going to RDWHAHB, but I'd like to know as much about my beer as I can. Thanks!

Its too early to tell anything except that you are going to get bacteria if you keep opening your fermenter. Leave it for another week, then take your hydro readings. The taste will change over time. There is nothing really to learn from samples taken this early. Try some when you bottle/keg, then compare that to what you have 3 weeks later. I tell non-homebrewers its like cooking a meal and not knowing how its going to taste for 6 weeks.

To answer you question . . . I can't. There are so many chemical processes going on it could be many things.

I think no one cares actually at this point in the process.

Sounds good. I need to get me a bigger pipeline...