user24103: 
In this position, black's king is safe, has a secure queenside pawn structure, and has taken out white's left pawns and is up 2 points of material.  Despite this, lichess evaluates this position at +3.5.  Why?

user15478: [FEN "r4rk1/2p1qppp/1p3n2/p7/2B4B/4P3/PPQN1Pbb/2KRR3 w - - 0 1"]

1. f3 {traps the bishop} Rad8 2. Re2 Bxf3 (2...Bd6 Rxg2 Kh8 Rh1 {the Black king is not safe at all}) 3. Bxf6 Qxf6 (3...gxf6 Rxh2 {checkmate on h7 will follow}) 4. Rxh2 {threatening mate on h7} h6
5. Rf1 {the bishop is now pinned against the queen and will be won shortly} b5 6. Be2

f3 followed by Re2 wins a bishop (Re2 Bc6 f4 wins the other one), and with no pawns on the h- and g-files it will become evident that the Black king is not safe at all. This solution is simple enough to gain a significant advantage (+2). But there is an even more brutal sequence that wins both bishops with some finesse.

24103: <p><a href="https://i.stack.imgur.com/B9t8a.png" rel="noreferrer"><img src="https://i.stack.imgur.com/B9t8a.png" alt="the" /></a></p>
<p>In this position, black's king is safe, has a secure queenside pawn structure, and has taken out white's left pawns and is up 2 points of material.  Despite this, lichess evaluates this position at +3.5.  Why?</p>
 15478: <pre><code>[FEN &quot;r4rk1/2p1qppp/1p3n2/p7/2B4B/4P3/PPQN1Pbb/2KRR3 w - - 0 1&quot;]

1. f3 {traps the bishop} Rad8 2. Re2 Bxf3 (2...Bd6 Rxg2 Kh8 Rh1 {the Black king is not safe at all}) 3. Bxf6 Qxf6 (3...gxf6 Rxh2 {checkmate on h7 will follow}) 4. Rxh2 {threatening mate on h7} h6
5. Rf1 {the bishop is now pinned against the queen and will be won shortly} b5 6. Be2
</code></pre>
<p>f3 followed by Re2 wins a bishop (Re2 Bc6 f4 wins the other one), and with no pawns on the h- and g-files it will become evident that the Black king is not safe at all. This solution is simple enough to gain a significant advantage (+2). But there is an even more brutal sequence that wins both bishops with some finesse.</p>
