Why did Harvey and Jessica deceive Mike about their ploy regarding Monica and Hardman? After all, Mike's on their side. Well, remember, they know Mike's not quite tough thanks to the mock trial, but they need him to be - so him acting out of his idealism and loyalty is more useful than trying to get him to be dishonest. Also, Louis seeing Mike is integral to the ploy - any sign of falsehood, Louis might see. Lastly, they're also trying to protect Mike - his part ends up looking like a mere pawn rather than a valuable player; if their ploy failed, Hardman would be less likely to hurt Mike as much comparatively. Hardman might even try to use Mike later if he thought Mike was still useful in some way.
Harvey's and Mike's tragic success is heartbreaking, yes. But you know how Jessica has noted that Harvey is similar to Hardman and that Mike is similar to Harvey? On a broader scale then, their tragedies are suppose to be similar to Hardman's - doing something else rather than spending time with family. In Hardman's case, however, rather than getting caught up in work, he gets caught up in panties.
In the first season, Mike has to practically drag Harvey into a fist bump. Now, they gleefully play HORSE in the office together. It's not because Harvey has become less of a stickler for such things, but rather, he's now more comfortable with Mike and more willing to open up and seem vulnerable (or mortal, at any rate).
Fridge Brilliance about Harvey's Honor Before Reason tendencies in regards to the truth and his unwillingness to lie. Among other things, he had to lie to Dad every single day about something truly important. And then his time with Cameron Dennis, he had to lie to win as per Dennis' MO.
The reason Louis is so good at financial crimes? Because as Harvey points out in a different context, Louis thinks underhandedly by default; it's only Louis' loyalty to P&H that keeps him otherwise in check.
On Harvey's adamant devotion to sticking to his word and his promises. His parents made a promise to each other. One of them broke that promise and caused a lot of pain and a lot of lying.