Player: “Ok, I’m going to move 30 here and use my sneak attack on the last- oh wait, I can’t, nevermind.”
Me: “Wait, why?”
Player: “He’s out of range by 5ft, I have disadvantage so no sneak attack.”
Me: “Bro just roll sneak attack, he’s the last goblin. We have cooler shit to get to this session.”
Player: “So, advantage?”
Me: “Yes advantage. Please don’t make me play one more round as this 7HP cannon fodder.”
For combat, i mostly go strict by the rules, but i encourage my players to do interesting stuff, like movement, jumps etc. and im not that strict by handling that. Generally i try to make combat not a slog to roll through, but something fun and exciting. Not that easy, but i love printing minis and building cool maps.