A condescending look on his face, browsing around for impurities, things not supposed to be where they are, not supposed to be how they are. Always knowing better.
To the middle-aged lady struggling to be gracious while slicing a banana in her yogurt - he felt the need to let her know the unnecessary and perhaps even painful labor she'd put her digestive system through: fruits do not belong in a meal; one should have them at least half an hour before or after a meal. Your stomach will thank you for it and your day will run smoother and you'll be happier.
To the gentleman pouring a drop of milk in his cup of filter coffee - better not. Coffee is much more efficient without the milk. And milk? Who does actually still need that?
To the lady packing up a few sandwiches for her husband and daughter and wrapping them in a napkin - "I cannot help myself to be rather distressed by what you are doing", he says. He did not wait for her explanation (her husband and daughter are going to miss breakfast this morning since they are too tired to wake up and will have to leave in a few minutes anyway) and disappeared behind the front desk. Two minutes later, he came back and very calmly, without even trying to hear what the woman had to say, he let her know that - one: her action was a sign of unfairness towards the other guests and - two: that he will not be able to guarantee the freshness of her sandwiches if they are not consumed during the breakfast time and within the hotel perimeter.
He poked a peach from the breakfast bar, refilled the water jug and looked out the window, immersed in thoughts.