When Ivor Novello is playing piano and singing in the drawing room after dinner, the aristocrats are polite - applauding after each song - or snippy, as with Lady Constance ("Please, don't encourage him"). The servants, however, are enraptured, listening to him play while in the hall behind closed doors, and it's kind of touching to see them having fun like this.
Also turns into a Crowning Moment Of Awesome for Mrs. Croft; when Mrs. Wilson finds everybody listening, she snaps at them and tells them to get back to work, but Mrs. Croft stands up to her and says it's okay if they take a break for a few minutes.
When Mr Meredith is having a sulk in the pantry and starts complaining to Dorothy, who tells him:
I believe in love, love, not just getting it, but giving it. I think that if you're able to love someone, even if they don't know it, even if they can't love you back, then it's worth it.