At some point, when I was young, I learned an opening that involves the following moves: possibly after moving queen's pawn to the centre (
d4), move out king's knight to above the bishop (
Nf3), move knight's pawn up one (
g3), move bishop up behind knight's pawn (
Bg2), castle on king's side (
O-O). This results in a very tight and turtle-like defensive formation that was sufficiently aesthetically pleasing to my young self that, in the years since, I've found it quite hard to get out of the habit of using it as my opening. (I'm not a chess expert in any way, I hasten to point out if it's not already obvious, though I do usually beat other casual players.)
Is this a well-known opening and does it have a name? Given my apparent overwhelming predilection for playing it, what are its advantages, and what weaknesses does it have that I should watch for my opponent being able to exploit? Any recommendations for taking my opening game to the next level would also be appreciated!