|Diagram 1. White to move|
r3r1k1/2qn1pb1/p5p1/6P1/2p5/1N2B2Q/PPP4P/2KR1R2 w - - 0 1
On both PoPs (Points of Pressure) are B.A.D. (Barely Adequate Defended) pieces.
It is a common scenario. You can take a hanging piece, but you have to defend against the counter attack. The white queen has the Function to defend e3, and is partly immobilized because of that.
|Diagram 2. Black to move|
2q2bk1/R3r2p/6p1/3nB3/8/1p3N1P/5PPK/Q7 b - - 1 1
The white bishop is partly immobilized because its function is to defend the LoA b8-h2.
The white queen is partly immobilized because its function is to defend a7.
|Diagram 3. White to move|
3rrk2/p1R1Nppp/8/3b4/4n3/P5P1/5PBP/4R1K1 w - - 1 1
Both the white knight and the black knight look B.A.D..
But the LoA e1-e7 happens to cover both.
|Diagram 4. Black to move|
2r2qk1/6pp/Q1Np4/4p3/P5b1/8/1r3PPP/3R1RK1 b - - 1 1
A scenario that happens time and again. White can take the exchange d1 for free, but must at the same time protect c8 against the knight fork. The black bishop is partly immobilized because of its Function to protect c8. Is there a LoA that defends rook c8 with preservation of the initiative, so that the black bishop is relieved from its Function with tempo? That leads to a move which would otherwise be incomprehensible.
Btw check out the ratings of the problems.