I just ignore them. Then again, after an anime marathon lately, I've found myself wanting to say "demo" a lot. I've never learned Japanese and don't really plan to, so I can only guess from the subs that it means something along the lines of "but". I find it amusing that all my favourite shows use the word "but" so often that it actually filtered into my brain :) ... ... (thankfully, I'm still controlling it. Might slip out one day, though)