In A Midsummer Night's Dream, what are some examples of characters showing good intentions but ending up making the situation worse?

As befitting one of Shakespeare´s romantic comedies, this play is all about mistakes, confused identities, and problems becoming further complicated before they are resolved. The key example of one character who tries to help and resolve the problems in the play but laughably only succeeds in making things worse is Puck, who is ordered by his master, Oberon, King of the Fairies, to make Demetrius fall in love with Helena. Puck and Oberon have observed how much in love Helena is with Demetrius, but how he treats her, insulting her, threatening to abandon her and lastly threatening her with violence if she will not leave her alone. Oberon thus decides to reverse things and make Demetrius fall madly in love with Helena:

Fare thee well nymph, ere he do leave this grove,

Thou shalt fly him, and he shall seek thy love.

Of course, hilarious confusion results, when Puck, not knowing there are two Athenian couples in the woods, annoints the eyes of Lysander with the flower, and then Helena wakes him and Lysander suddenly is in love with Helena, completely forgetting Hermia. This situation is further complicated (as if it couldn´t get any worse) when Puck annoints the eye of Demetrius and then Helena is the first person he sees, resulting in a complete reversal of affections from the beginning of the play, when Hermia was loved by both males. Now, Helena is loved by both males and Hermia is rejected by them both. Of course, by the end of the play, Puck has resolved his mistake, separating the lovers and re-annointing their eyes, ensuring that they wake up with the right person.

Of course, all of this serves to highlight a central theme of the play - the fickleness of love, and we can´t help but laugh at characters who one minute swear their undying devotion to someone else, then next minute completely forget them. The last laugh seems to be with Shakespeare however, as through all of this he is mocking our fickleness and inconstancy and our ability to radically change our affections. By making us laugh at characters who do what we do, he makes the lesson much stronger.