It doesn't matter how well-honed your guitar chops are, the way your instrument is set up will have a huge effect on how ...

Heavier strings will pull more on the guitar neck, which can cause the action (string height) to go too high, whereas a lighter gauge doesn’t pull as much, resulting in an action that’s too low.

Put simply, it's the height your strings are set from the guitar's frets ... It's a very personal thing, and when your string gauges are on the heavier side that also affects how physically ...