fjd wrote on 12/18/18 at 15:40:51:
Well, as a kid I was taught that if you can't go ...Bb6 in reply to Be3, you play ...d6 and aim for the structure with pawns on c5 and e5. That being said, I'm not sure how well the "rule" holds up that you should never take on e3 in these stand-offs, given that White seems to be doing the same thing in reverse all the time these days.
The Giuoco Pianissimo with Nc3 is seen ad nauseam in junior chess. I suppose it seems a natural next step to them, after they've given up playing for Scholar's mate and learned the importance of development and the centre.
The main problem is that the position is so closed, and they can't use their rooks. So coaches often encourage students to play Be3/Be6 to invite the opponent to open the f-file; at junior level the half-open f-file can soon become a decisive plus.
Conversely students are advised to reply to Be3/Be6 with Bb3/Bb6, when if the opponent exchanges one gains the half-open a-file and potential knight outposts at d4/d5 and f4/f4.
Theoretically, though, things are less clear. While Tarrasch was adamant that one should not exchange (on e3/or e6), Steinitz advocated exchanging, since he considered the long term damage to the enemy pawn structure (and reduction in flexibility) to be more important than the extra piece activity granted to the opponent. For instance, against Lasker he played 1. e4 e5 2. Nf3 Nc6 3. Bc4 Bc5 4. Nc3 Nf6 5. d3 d6 6. Be3 Bxe3 7. fxe3 Na5 8.Bb3 Nxb3 9. axb3 Ng4 10. Qe2 f6 11. d4 c6 12. O-O-O Qe7 13. h3 Nh6, with a sold and flexible position, although he lost later.