Putin's fears before Crimea were partially the west's fault, but after Crimea, Putin had no-one to blame but himself.
1. The Pro-Russian government was even more incompetent and corrupt than the current one
2. Before Crimea, many Ukrainians held a pro-Russia view on things, but this decreased dramatically afterwards
3. The annexation of Crimea made the Ukrainian elections more pro-western. The Eastern areas, including Crimea, were Pro Russian, and since there was usually a roughly 50% split, and Crimea held 5% of Ukraine's population, Putin made it easier for Pro Western candidates to win
4. Putin still invaded a sovereign nation, bombed civilians, and subjected young Russian teens and Ukrainian children, barely men, to the horrors of a modern war
You cannot have sympathy for Putin (The Russian people are a different story) after having read some of the letters that these soldiers send home