According to Nap, this is primarily a religious war being waged by Putin.
According to
@Rhakim, Ukraine should adopt a strategy of nonviolence against the Russian invasion.
According to the Putin-stans, NATO has been expanding in a threatening way ever since it's creation and this in itself is cause for it's invasion of Ukraine.
According to me, Putin has fantasies of recreating the USSR by retaking Eastern Europe through the degradation of their political systems and eventually by military means. Ukraine is well within their rights to fukk up any invading Russian on their soil until all land taken is back in Ukrainian hands.
That's about it in a nutshell.