That Makes Me a Saaaaad Thanos

It was instantly obvious and clear to me that this is a film about DEPRESSION.

ALL of the Characters appearing in it as featured protagonists are depressed when this film begins - INCLUDING THE VILLAIN.

Thor is the only one who openly gives in to expressing his depression (which is the best scene in the entire film, located right it's the emotional and chronological centre) when Rocket realises that the fate of the universe rests on getting him to open up to him and talk to him,  even though offering berevement councilling to a grieving God is the absolute last thing in the world he either wants to, or is equipped to or qualified to handle, except that aside from him and the tree, there is *literally* no-one else able to support him, or offer The God the help he needs in order to be able to do all the things he is still have to going to do, and be able to do perfectly, with total commitment and 1010% effort.

All for this guy who can't even be bothered to get his species right.

And so he simply just takes a deep breath, futzes around for a second or two with some random control panel and tells himself "Well.... I guess it's time to be The Captain..."

Even though they might not yet realise it, all their inner chess-pieces are aligned around their own personal emotional crisis and poised for imminent collapse, and having the very core of their being and sense of True Self undermined and fundamentally tested and challenged - I've actually gone back over these in my head to the point where I can actually specify the source for the loss of self-confidence for every single major character in it

But just to mention the three most obvious and non-spoilery example, stated in terms of Cause and Effect :

Hulk is *NOT* The Strongest There is  - therefore, he is essentially suicidal (remember, Banner said in the earlier film, which expresses itself