Carlsen vs Shirov, 2008 79 ... Kf6-e5?? blocks Black h2-bishop from b8-promotion square

Gu vs notyetagm Pawn Eater #102 2009
29 ... Nd5-e3? blocks White f3-rook from defending c3-square

Just for the record, I have a very bad habit of making this exact same kind of tactical oversight as Shirov's howler 79 ... f6-e5?? in Carlsen vs Shirov, 2008, losing control over important squares by <BLOCKING> one of my own line pieces that was <DEFENDING> an important square.

White to play: 27 ?

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Position after 27 b5-c3?! e4-g3

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Just this past Tuesday at the Metrowest Chess Club I played 27 b5-c3?!, <BLOCKING> my White b3-rook from <DEFENDING> the important weak squares e3 and g3 near my castled king. After 27 ... e4-g3 I failed to find the only move 28 f1-b1!= box and lost.

Hopefully this simply -incredible- blunder 79 ... f6-e5?? by Shirov will burn this idea deep into the chess understanding part of my brain and I will stop making moves that make my life difficult like 27 b5-c3?!.