Not all of your examples are simply hubris (although there certainly was some of that).

> Enjoining WW1 was completely unnecessary

It effectively was necessary. They were drawn it via a pre-existing treaty with Belgium; it also does not seem like a good long-term plan for them to allow Germany to dominate the entire European mainland. The whole thing was a mess, but not because Britain was out of touch with the reality of the situation. They were very aware but felt they had no choice.

> The Treaty of Versailles was painfully myopic - all but ensuring WW2

It was, but that's a perspective that's very clear in hindsight, and at the time it arose more from ignorance of the consequences (and possibly some vindictiveness) than hubris.

> that's a perspective that's very clear in hindsight,

It was clear at the time at least to people like Keynes who wrote a book on the subject: The Economic Consequences of the Peace.

"My purpose in this book is to show that the Carthaginian Peace is not practically right or possible. Although the school of thought from which it springs is aware of the economic factor, it overlooks, nevertheless, the deeper economic tendencies which are to govern the future. The clock cannot be set back. You cannot restore Central Europe to 1870 without setting up such strains in the European structure and letting loose such human and spiritual forces as, pushing beyond frontiers and races, will overwhelm not only you and your "guarantees," but your institutions, and the existing order of your Society."

There's a decent Wiki page on Britain's entry into WW1 here. [1] Britain's cabinet had already decided, before they chose to declare war, that the treaty did not obligate a military response.

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"Few historians would still maintain that the 'rape of Belgium' was the real motive for Britain's declaration of war on Germany. Instead, the role of Belgian neutrality is variously interpreted as an excuse used to mobilise public opinion, to provide embarrassed radicals in the cabinet with the justification for abandoning the principal of pacifism and thus staying in office, or - in the more conspiratorial versions - as cover for naked imperial interests."

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Similarly many people were fully aware that Treaty of Versailles was foolish as it was being drafted. Its excessively punitive nature essentially precluded any sort of peaceful reconciliation, which should always be the goal at the end of war. You never know who your allies, or your enemies, will be in a few decades. History loves a plot twist.

[1] - https://en.wikipedia.org/wiki/British_declaration_of_war_upo...