Hi I know that this issue is brought up a lot and I could not find an answer to my questions in my search. I am trying to adjust my RD (Shimano 105) to dial in my shifting and when I have it on my stand I can get it to shift pretty well but when I take it around the block to test it out I have a few issues. My larger cogs seem to shift pretty smooth but when I get towards the larger cogs the shifting becomes very clunky. It seems like when I click to shift that it shifts really loud and rough. Also I have one cog somewhere in the middle (cant remember exactly which one because it was a few hours ago when I was testing it and forgot to note exactly which one) that it wont shift into until I click one more gear. I am fairly new to cycling and learned to adjust my RD on my own so I am looking for any advice. (also from what I can tell my RD hanger appears to be straight and not bent) My questions are:
1. Why do some gears shift smoothly while others are rough/clunky and how do you fix it?
2. Why would only one gear not shift correctly but the rest do and how would you fix that as well without messing up the rest of the shifting?

Hopefully I gave you enough information and if you have any other questions just let me know and I will try to answer them as soon as possible. Thanks