Seriously, would it kill Oliver to say to Felicity what Diggle said to her? Instead he's "reunited and it feels soooo good!" with Sara and now he's all snappy and terse and back to before he and Felicity made their connection. And didn't he say he didn't want to get involved with someone he could care about because of the nature of what he does? He should have just said "Felicity, I'm just not that in to you". Maybe this is the writers way of slowing things down between the two of them before building back up to happily ever after. One could only hope!