In one episode late in the series, Richard gets fed up with Hyacinth hassling an innocent passer-by in a phonebooth and forcefully orders her to stop. Hyacinth is so shocked that she wordlessly complies.
When they get stuck in a field in the Cruise Special, Richard tells Hyacinth to go out and push the car. She gets sprayed with mud. Adding to the Humiliation Conga of this event, Hyacinth follows it up by saying, "You'll pay for this, Richard Bucket!" and actually pronouncing the name as it's spelt. She quickly corrects herself, but it's one of the only times in the entire series she slips on her Insistent Terminology.
The Cruise Special was a huge moment of awesome for Onslow. He had won cruise tickets for him and Daisy. We see him with some very nice suits and he's on a higher plane than Hyacinth for once.
Also, somehow Hyacinth manages to get in touch with the bridge of the QE2 from the dock office, and the first officer still says, in no uncertain terms, that they cannot come back for them and it's not their fault that Hyacinth and Richard were late. Gotta admire the unflappable demeanor of the British sailor!
OK, we'll throw in one for Hyacinth, but just one. (This moment may also be considered a Heartwarming Moment of sorts.) At the end of the same mentioned special, she finally gets that Onslow and Daisy were not stowaways (as she's been thinking throughout the episode) but instead guests of honor because the couple won a giveaway. During the dance party, when the guests go onto the floor, Hyacinth actually goes to up to Onslow to congratulate and dance with him (albeit rather begrudgingly). As she dances alongside who is usually the last person that she wants to be around with, Hyacinth dances with Onslow more and more aggressively until the spotlight shines brightly on the two of them. They then boogie down to the song as they become the center of attention, seemingly enjoying the moment as the credits roll. Now granted, she most likely did this just for the attention, but Hyacinth actually having fun with Onslow comes across rather sweet... sort of.
Another instance for Hyacinth occurs when another failed scheme to impress a business figure has Richard stifled by a yob. His mate gets on his motorbike to harass an enraged Hyacinth, who clubs him off with one shot of her bag. Said businessman is so impressed by this act he gives Hyacinth an offer instead of Richard, however she gladly denies it, she couldn't bear to leave him at home all by himself (to his dismay).
Basically anyone can who say "no" to Hyacinth deserves a mention.