It was clearly wrong of Putin to invade the Donbas area of Ukraine in 2014 - Ukraine is a separate country with clearly defined international borders, at least since 1945. The Russian position on Crimea is SLIGHTLY less clear; Crimea became part of the Russian Empire in 1783 (it had been in the Turkish 'sphere' up to then) and it was only in 1954 that it was 'transferred' to Ukraine. To most Russians it is really still part of Russia. I doubt most of Ukraine's allies will not 'forgive' Russia until the Donbas is returned to Ukrainian control - possibly with more local powers than other regions. If 'only' Crimea is not back under Ukrainian control I suspect 'things will return to normal'. (Or at least the new normal.)