It is well known in Kabbala and Chassidus that Shmiras Habris, guarding ones purity, brings to הכנעה - holy submission. That is why Yosef, whose uniqueness was that he was the quintessential "Shomer Bris", was called the משביר of Mitzrayim. משביר in its simple meaning in this context means that he sustained Mitzrayim in their time of hunger but it also means that he was שובר - he was "broken and submissive". The primary tikkun is to have a לב נשבר - a broken heart and OF COURSE it must be with simcha.
When someone thinks that he is a "gantza yeish" - a supremely important personage, then he is setting himself up for frustration, disappointment and pain. People are often not going to see things the same way and will not show him the respect he thinks he deserves and he will be hurt. When a person has הכנעה - holy submission, he can't get offended because he has no delusions of grandeur.
Sometimes people treat me like garbage. It hurts and infuriates me. I think of my "many" fine qualities [real or imagined] and wonder how this person can treat me like that. But then I consider what Dovid Hamelech said - אנכי תולעת ולא איש חרפת אדם ובזוי עם - I am a worm and not a man, a disgrace of a human being. If the King Of Israel can say that, what about me?? This feeling of הכנעה brings to great simcha. I am no longer a servant to the way other people relate to me.
The pasuk in Tehillim says הרופא לשבורי לב ומחבש לעצבותם - The Yid Hakadosh interpreted that this means that Hashem heals our hearts so that they can be broken without sadness.
Moira-dik!
One important factor in this project of הכנעה בשמחה is Shmiras Habris.
[Based on the sefer Oros Yismach Yisrael (from the Rebbe of Alexander) Page 67]