"thanks" salutations, greetings, and any extraneous text in the question, is (no offense) but a wast of time to everybody that comes along and reads it.
All extraneous text should be edited out of posts.
If you have a line at the end of your question that says:
I would really appreciate any help with this.
Thanks in advance.
Sure is it "harmless" it only take what 2 seconds to read. But it is useless to the question. I can answer your question just as well if that was not there. Now what if your question was viewed by 200 people? You've now wasted nearly 7 minutes of peoples' lives just because you wanted to be polite.
Save the thanks for when you really do get that answer. The green check mark to the left of an answer is a great way to show the answer helped you.
There is a plethora of info on this all over SE.
This guy here has a good answer on concisely conveying the relevant information, with quite a few relevant links.
He even asked a question about it Editing questions to remove “thank you” etc.
Comments are another matter entirely (well for me).
I too have the same frustration about "thanks" in the comments.
I mean what is the big deal? It a comment. I often express thanks for a particularity good answer.
Comments by design are not meant for long term information, they get deleted and cleaned up often. I for one have no problem with a thanks comment. However SE thinks otherwise, and we have people that go around flagging "thanks" comments from data queries.
So your thanks comment probably will get deleted at some point. Don't sweat it. The post author will get notified of your comment, and he is really the only person that needs to see it. (As a mod I often leave comments on posts I'm about to delete. My comment get deleted, but the OP will still see it.)
TLDR (yes I put it at the bottom so you had to read the posts first)
Keep any and all extraneous text out of posts.
I'm ok with a thanks comment, but don't tell SE I said that.