I'm not weird. I'm socially challenged.
Yeah, i usually don't know what to answer to nice comments beside "Thanks".
If someone ask me something, criticize, or whatever, i'm pretty quick to answer. But, when it's just a nice comment, i got nothing. For ages.
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Bluekett
"Thanks!" is an infinitely better response than "But it sucks." and unfortunately I hear the latter a bunch from very skilled artists.
Don't worry about responding with a "Thanks" because people rarely expect much more than that when they leave a comment, shoot, it's already a super nice gesture to take your time to respond at all!