Euromaidan (Nov 2013, leading to the Revolution of Dignity, Feb 2014) seems to be one of the main things that pissed Russia off, that made them fear for their national security. Here's the people of Ukraine, showing hope & trying to cast off the corruption, unwilling to simply swallow the long dark agenda their leaders are pushing them towards. Amazing.
Having hope & democracy & people getting better is an existential threat to a nearby country that rules via corruption & force. Ukraine has improved slowly, moved up in the ranks of corrupt countries, passed Russia (now #122 vs Russia' #136 in the Corruption Perception Index, https://www.transparency.org/en/cpi/2021 ). The model of people being free to speak up against the bad is a primary threat, and happening too close to Russia for them to bear it.
As FP put in the Dec 2021 subheading,
> The country’s democratization and ongoing efforts to fight entrenched graft and cronyism are a threat to Putin’s model of governance.
https://foreignpolicy.com/2021/12/17/ukraine-russia-corrupti...
