Boros Energy is an aggressive creature deck full of small efficient threats like Ragavan, Nimble Pilferer and Ocelot Pride, so Lightning Axe's 5 damage is clean, cheap removal that kills essentially anything they play. Surgical Extraction can strip a copy of a key card like Ragavan or Ajani, Nacatl Pariah out of their deck once we see it in a graveyard, denying future copies in a grindy racing matchup. Golgari Thug is a weaker body against their aggressive curve and doesn't block well, so it's trimmed, and Artist's Talent's incremental filtering is too slow when we need immediate answers to their threats. Watch out for their Blood Moon, which would strand our nonbasic-heavy manabase, but we have no clean answer to it in the sideboard so plan around sequencing basics if possible.

Affinity fills the board with cheap artifact creatures like Pinnacle Emissary tokens and Kappa Cannoneer, so Pick Your Poison's -2/-2 mode is a great sweeper against their small Drone tokens and can even help against Kappa Cannoneer early. Lightning Axe cleanly kills Pinnacle Emissary and is easy to pay for given our card-heavy hands. Golgari Thug's small body trades poorly and doesn't advance our plan fast enough against their explosive curve, so it's cut, and Artist's Talent's slow value engine doesn't help us race a deck that can kill by turn 4. Although Vexing Bauble can counter free spells here since Affinity's card advantage (Mishra's Bauble) costs no mana to cast, it stays in the sideboard.

Izzet Prowess is a fast aggressive mirror of the graveyard/spells plan, so Lightning Axe is excellent removal for Monastery Swiftspear or Dragon's Rage Channeler before they get out of hand, and the discard cost is trivial in a deck full of extra cards to pitch. Boseiju, Who Endures comes in as a land that can later Channel to blow up a problematic artifact like Cori-Steel Cutter or a nonbasic land, replacing lesser lands is not needed so we swap it for two Golgari Thug copies since their low-toughness aggressive plan punishes our slow dredge engine. Vexing Bauble is tempting since free spells like Mutagenic Growth (paid with 2 life) give it real targets and it could be considered, but we prioritize removal instead since racing matters more than countering pump spells. Artist's Talent is cut because we're not looking to grind incremental card filtering in a race we need to win on damage and removal.