Here's the thing: do the signing, sign the things.
When I went to my first juggling convention in the USA, back in 2004, I was taken aback by how many jugglers wanted me to sign stuff. Mainly because in the UK and Europe nobody gives a shit about stuff like that, but also because while I was internet famous, I hadn't been anywhere where I'd consider myself actually famous.
First I turned down autograph requests, and then I moved on to signing things in a way where my signature was hard to read or in a weird inaccessible place. But soon I noticed that the things I was asked sign, generally juggling rings or convention programs or promo material, had lots of other signatures. I asked around, and was told by the famous American jugglers there that it was the done thing.
And I soon realised they were exactly right. No matter how uncomfortable or weird I felt about signing stuff, I only came off as a dick to everyone if I didn't do it. If I did sign stuff, I only felt like a dick to myself. There was never a moment where I was famous enough that anyone would care that I WAS signing stuff, in that they thought that I thought I was someone big and famous when I wasn't.
Anyway, you can game-theory this all out, and it signing stuff only has upsides to everyone, including yourself.
Still feel weird whenever I do it though.