Arrow, Season 5 (2016)

Oliver Queen is the mayor of Star City by day, but by night he is the masked vigilante who patrols its streets.  Through his efforts in these twin roles, and with the help of compatriots new and old, he hopes to stem the city's seemingly inexorable decline towards squalor and lawlessness.  Yes, there is irony in the fact that he wages a large part of this crusade via technically illegal means.  Oliver's not really the kind of guy to see the funny side of it, though.

And neither are his enemies, one of whom begins a vast, coordinated campaign to not only tear down Oliver personally, but to invalidate the very foundations of his quest and destroy everything he believes about himself and the world.  

Unfortunately, I found that vast, coordinated campaign to be horribly contrived and overwrought, with this season's nemesis apparently being some kind of super-genius or mind-reader who always knows exactly what Oliver & Co are going to do, even when they deliberately try to go against their own instincts. At several points, the villain's actions would be pants-on-head stupid if they didn't have 100% foreknowledge of the script.  And frankly, even with that foreknowledge, their ultimate scheme is pants-on-head stupid anyway.

The above paragraph may be a controversial opinion, as I know some people - including the show's lead actor - really like this season's villain.  One argument I have seen for this is that he is a good villain because his issue with Oliver Queen is personal, rather than merely a case of the Arrow being in the way of his schemes.  To which I say: meh, this was true of season 2's Deathstroke, as well, and that arc built on material we'd already seen in season one, rather than being invented whole cloth at this late stage.  Also, I'm beyond tired of Oliver Queen's manpain, and his whole storyline wallows in that manpain ad infinitum.  That in the process it also sabotages the Arrowverse's version of one of my favourite DC comics characters is the final cherry on the top of my discontent.

Definitely a highly qualified recommendation on this: if you're not planning to watch Arrow all the way through, I actually recommend you quit watching at the end of season three.