Being a persistent loser you should probably choose to disregard this comment, but (for those of you who know me will understand) I couldn't resist myself ...

I find that when the opponent castles it is a benefit to me as I know which side of the board to concentrate my attack on, this is particularly so when castling happens early in the game and piece development is still underway (so many pieces and so many places to put them!). I realise this is a somewhat simplistic assessment, but maybe that reflects my shallow play :(

This is, in part I believe, due to the number of diagonal pieces (four) available which can hone in on the corners (there is even one more in Janus Chess but in that variation there seems to be less castling, but let's not go there right now) and the width of the board makes it easier to position in threatening, yet distant, locations.

So, as a defensive move I try to castle after the opponent and to the opposite corner depending upon where their pieces are ...

and this, of course, relies upon me lasting that long :)