Both Molly and Issa need to go to therapy. They are both messy in different ways and both have not been good friends to each other in different ways for a while now. This may have prompted their growth which they both now fail & hate to see in each other.
#InsecureHBO

For one by design of the show and the story telling, we see things mostly in Issa's perspective. It's her story with a couple of objective snippets. It's therefore easier to identify with Issa than with Molly because we know more about Issa's motivations, fears, intentions etc.

However, both Issa and Molly were more critical than supportive to each other as friends. They both have zero communication skills. They are both not emphatic to each other. Although in varying degrees and on different topics.

They look at where they perceive inadequacy in their lives (Issa in proffessional; Molly in personal) and compare their perceived success (Issa in personal life; Molly in professional life) to their friend. I use perceive because the reality is not so binary.

Issa's professional life sure was messy but Molly has also been experiencing problems in hers (both at white & now black firm) but the friendship allows Issa to complain about professional challenges.

Molly's personal life is a mess but so is Issa's but the friendship only allows Molly to complain about this. Issa wants more in her personal life like Molly in her professional life.

For one, why couldn't Molly listen to Issa when she kissed Daniel, way before fucking him, instead telling her she's lucky? And also why did Issa never allow Molly to speak about her work when Molly would call her, instead Issa would complain about hers?

Because both think the other one is lucky and successful in those areas and should never complain about them. This was the fundamental problem in how they related to each other. They saw each other as Goliath in those areas with just an Achilles heel where they think they succeed

Issa is always dependent and comparing herself to others to succeed in her professional life. Molly is always doing the same in personal life. Issa also feels like she's not living her best personal life. That's why she has an alter ego that's more frank & sexually liberated.

Issa rationalises her feels of inadequacy with lack of financial means, when it's actually a lack of courage to live her best life unapologetic. This is linked to her relationship with her and her brother's emotionally unavailable mother. Her brother went to therapy though.

To live life so courageously is something Issa envies about Molly. Issa has been a good girl in her dating life but never reaps the rewards for this. That's why she felt like that about Daniel after they failed to have a long distance relationship and later Condola and Lawrence.

Molly is always comparing herself to others in her personal life: her mother, Issa, Tiffany, Asian colleague, Candice etc. She met someone who wanted her aggressively, the dark skinned guy. Alas, the grass is always greener. Her therapist warned her about magical/wishful thinking

Many threads show that Molly is a shitty friend, I will not go there. Also, Issa is a shitty friend to Molly. She's hardly ever there for Molly or emphatic to Molly's dating life, except to point Molly's shortcomings.

This is the same girl, who's been holding Issa down through her dating mistakes; warned her after that Kiss with Daniel not to entertain him but Issa went on to fuck him. Still she accepted Issa and (erroneously) gave Issa advice to keep her relationship with Lawrence.

Molly was unjudgemental and was there for Issa after the break up. She left Malibu (Kelli's bday) at 2am driving Issa to Inglewood risking DUI as an attorney (and her career) and came back to comfort her. She literally pretended to be seeing a client outside Lawrence's offices.

So Molly's been supporting Issa in her personal life and professionally, all that donating, giving her time and linking her up, only for Issa to fuck things over. Molly has been there for Issa from jump.

Also, the fact that Molly can be vulnerable about her inadequacy, her personal life, while Issa can't ask for financial help, is either showing Molly's an uncaring friend or Issa's a proud friend or both.

To conclude, Issa also found comfort in having a friend like Molly because even though Molly's successful and rich, at least unlike Molly, she's not lonely and miserable and can keep a nigga. The same way Molly found comfort in Issa's financial and professional challenges.

Both Issa and Molly's growth has brought to light these shortcomings and therefore put their friendship to this existential crisis. Issa (and Molly) is becoming successful in an area where Issa (and Molly) thought she was more successful?

They don't want to admit this to themselves and to their friend. Also, they don't know how they will relate to each other now. So, they choose to not accept the other's growth.

That's why from the beginning of this season they have been taking cheap shots on each other based on past evidence which no longer holds. That's why they can't communicate and would rather fight about it. It's a manifestation of an internal struggle about how they see themselves

Both Molly and Issa are insecure.
The lesson for us is: people need to love themselves unconditionally before they can love others and and define success for themselves not in relation to others. Most of the time we think this includes just sexual partners but it include friends.

This dynamic between them is interesting because it's possible between Kelli and Tiffany. It's also possibly between an SA celeb and his bestfriend. It's also of personal interest because it play in my friendships too: between me and some friends and between some of my friends.