It's not second thoughts; the reason for the lack of serious adventurism in the Middle East on the part of the Europeans is that there isn't much value to be gained, except oil, which is already within the West's influence.
None of the regional Muslim countries poses any threat to the EU as a whole. Lastly, they hate American adventurism as a result of these conflicts, which have created a backlog of refugees in the system, and locals feel their own culture and identity is being encroached upon and given rise to far-right parties.
Now, the latter point on the far-right parties can possibly come back to haunt the Muslim countries.
But make no mistake, if and when the European's want to fight, they are more than ready to tear a hole in the MENA region and wouldn't be kind.