Harry loves his time at the Grangers.
Dr and Dr Granger are the best!
Harry soon learns that both Grangers have PHDs. He's told to call Hermione's father 'Hugo' and he's so kind to him! Harry's aware he doesn't have anyone to compare him to (Vernon doesn't count) but he is still firmly of the opinion that he's great. It's the exact same situation with Hermione's moth- Emily.
Harry sometimes wonders why his upbringing didn't turn him into an ardent Muggle hater and people like them remind him why not.
The first time Harry argues with one of Hermione's parents leaves him reeling.
They were going out for a family dinner which he didn't want to attend. (A. Because he doesn't like going out to eat and B. Because he's not really family). Hugo gets annoyed at this. Harry - poor, oblivious Harry can't figure out why. If that doesn't tell you something about his life with the Dursleys, nothing will.
It takes an hour of shouting and screaming and arguing and the Grangers miss their reservation.
It all ends with Harry's breakdown. To his horror, it all comes spilling from him. Harry's not in the habit of revealing his - well he wouldn't call them secrets, maybe private memories or feelings? By the end, he is completely mortified. He has never, never broken down like this before. Aunt Petunia would have done much worse than try to hit him with a frying pan.
He doesn't realise that he's vocalised that until he sees Hermione's face twist in anger. He doesn't flinch - this is Hermione, his sister in all but blood, and he trusts her. He knows she's not perfect - he's argued with his sister. It was an absolutely terrible feeling and he hopes it doesn't happen too often: it's rather unenjoyable.
Harry is drawn from his reflection when warm arms wrap around him and he basks in the feeling of being cared about enough to be comforted, to be at least liked if not loved. He looks up - it doesn't feel like his sister's arms. He is stunned to find that it is in fact Hugo. Soon he relaxes - until Hermione decides to launch himself at him. For some reason, this act makes him start laughing. Hysterically. Soon, not to be outdone, the Grangers start laughing to.
If Harry didn't know better, he would think they were holding some sort of laughing competition. Emily's sly smile does nothing to disabuse him of the notion.