We could argue that Malvolio bought this mistreatment on himself and perhaps deserved it after his bad treatment of the other characters;
In some way Malvolio thought that he had superiority over Feste and as a result treated him unsympathetically and intolerantly. He also put Feste down repeatedly.
Malvolio was also a killjoy and during the play he gave the impression that he enjoyed spoiling fun. On a positive note Malvolio seemed dignified and when he threatened Maria, he also puts across an air of stupidity.
Malvolio is a time pleaser and is full of self-love, these qualities of his are exposed many times during the play;
When he receives the letter in the garden it seems to work through his conceit and shows that he is full of the desire to think highly of himself. If Malvolio wasn’t all of these things, than the letter would not have had the desired effect.
Malvolio was also vain and stupid. His vanity is evident from Act Two Scene Two. Despite the difference in rank, Malvolio flatters himself that Olivia loves him. He imagines himself as ‘Count Malvolio’, elegantly dressed in a ‘velvet gown’ and administering a stern rebuke to Sir Toby from a position of authority. This train of thoughts shows the depth of Malvolio’s vanity.
His self-love is bought out further by his ridiculous behaviour towards Olivia when he thinks that she loves him, and also by his disregard of Sir Toby.
During the play when Malvolio makes himself look stupid, we the audience seem to find it funny. I think we find this funny because Malvolio sees himself as such a ‘dignified’ man, and it is almost ironic that such a supposedly ‘dignified’ man can make himself look so stupid so often.
The in which Malvolio is portrayed makes him the type of character that we like to see bad things happening to. He is the ‘baddy’ of Twelfth Night, and if bad things happen to the ‘baddy’ it usually means that the ‘goodies’ will triumph, which is usually always what audiences hope for.
When Malvolio is sent to prison, it seems that the joke has finally gone too far, as he has been put there wrongly. But in some ways we are happy to see Malvolio there because it means that he is out of the way and events can progress without his interference. It’s as though with Malvolio in prison, good things can start to happen again. I don’t think that by being in prison Malvolio really suffers, if anything it may be just what he needs to take along hard look at himself. But Malvolio still feels he has suffered and has been done wrong as being in prison will have damaged his pride and ‘dignified’ image.