[Every part of him that's a butler is upset down to its deepest core, yes. His smile softens all the same.]
Please don't apologise. In my world it would be unthinkable, but I realise this is not my world, and it's on me to adapt. [He's really mostly concerned about how it reflects back on Ciel, if his servant goes around being so casual.]
Besides, your own preferences certainly should be honoured to the greatest possible extent.