To start off I just want to say a few words; I HATE YOU NBC! YOU'RE A BUNCH OFF ASSHOLES WHO DON'T KNOW WHAT A GOOD SHOW IS! I HATE YOU! Right, now we've got that cleared up lets begin.
Point no.1; The titles of the episodes were simply, the best:
1. Non Est Asylum
2. The Darkness Beneath
3. The Devil's Vinyl
4. A Feast of Friends
5. Danse Vandou (my favourite episode)
6. Rage of Caliban
7. Blessed are the Damned (How can you not love that name)
8/9. The Saint Of Last Resorts, parts 1&2
10. Quid Pro Quo (Say that 10 times fast, I dare you)
11. A whole world out there
12. Angels and Ministers of Grace
13. Waiting for the man
With episode names like that, how can you not love the show. Sure some of them are weird to say or not even in English but you have to admit they're better then The Flash or Arrow or Gotham or even Smallville.
Point no.2; Matt Ryan
The actor backed up the show all the way till it's untimely demise. (^). I felt like he brought the Hellblazer we all know and love, to life perfectly. It wouldn't of been as great without him, so DC and NBC definitely made the right casting choice (which is more then can be said for Ezra Miller's Flash).
Point no.3; The action
When Constantine sets his hands on fire you know sh*t's about to go down. Each episode has amazing action and is tense all the way through. What makes it even greater, are the 'spells' (I don't know what they're called, magical chants?). The way they're spoken and the fact that you can never actually understand what he's saying makes it truly, amazing.