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fic writers love & appreciate comments with all our hearts. we do. but i wanted to make it clear that just because a writer doesn't respond to your comment, it doesn't mean they don't care about it or that they don't appreciate you reading their work. [thread]
i understand feeling ignored, or being anxious that the author didn't like what you said. partly i'm writing this thread to try and assuage those worries. readers & their comments mean the world to writers, your enthusiasm & encouragement is what fuels us!
i can't speak for every writer, but personally i know i read every comment on all of my fics. i try to respond to as many of them as i can, even if it's a simple "thank you!" however that's my own choice and not every author is obligated to do the same thing-
i sometimes see readers saying they don't feel the need to comment if the author doesn't respond to comments. and of course, no reader is obligated to comment. however, if that's the only reason you're not commenting, i just wanted to try and put some things in perspective-
think of fic comments as similar to leaving a tip at a restaurant. it's not necessary per se, but it's a token of gratitude. and you don't expect the waiter to give you a tip in return. they already provided the service for you.
this isn't a perfect analogy, because it takes less time to pull a few bills from your wallet than to type out a long comment. but hopefully you get what i mean. the writer already wrote & published an entire (free!) story. they don't owe a long response to every comment.
there's also a lot of other factors to consider i.e. the writer might have a lot of other comments to respond to, they might have social anxiety, they're not sure how to respond to something, they're overwhelmed with work/school/life/etc.
just speaking for myself (and i'm sure for many other writers too) comments can really make my entire day. i've gotten wonderful comments that moved me to tears. i wish i could respond to every single one. and i just hope readers know how much their kind words are appreciated.
so please don't feel discouraged from commenting on something solely because you think the writer won't respond (or that they'll only give you a short response). there's many reasons why they might not reply, but none of them are that we don't appreciate you. 
