Johan Hellsten is absolutely on fire with his videos for ChessDojo and ChessMood. (His book Mastering Chess Strategy would be my pick for best strategy workbook ever.) One of the ChessMood videos ended up having a serendipitous tie-in with something I was working on in my blitz games.
In this standard Carlsbad structure my opponent had just gone b4. I spent 34 seconds on my next move, a sure sign I was completely lost. (I find excessive time spent is just as good a signal that a moment in a blitz game is ripe for review as a big mistake.) The computer’s top choice is Bd6. After clicking around a little, I understood that the point of this move is to set up the e5 break. Responding to a flank advance with a break in the center! If I succeed in trading my e-pawn for White’s d4-pawn, c3 will start looking like more of a weakness, and White’s control of c5 will be loosened. It all makes sense, once you know!
I played Bg6 and ended up winning in a time scramble much later. Actually, this was the game I finally made it over 2600 on chess.com.
Anyway, a few days later Hellsten popped up with a great example of the same idea.
This is why I think blitz is useful for improvement. Between the game, the video, and now this blog post (!) I won’t forget that idea.