Have you ever done this?

My latest opponent opened with 1.Nc3 and I thought well let's transpose into a closed Sicilian and replied 1...c5. He then 'agreed' and played 2.e4 and I responded with 2...d6. He just played 3.Nf3 before I realized we weren't playing the Closed Sicilian at all. The actual moves of our game were 1.Nf3 f5 2.d4 e6 3.Nc3...

I had gotten the Queen and King mixed up. Now it'll probably be a Staunton Gambit.

Hahaha.

I recall playing that many Latvians at once I made a move and flicked
onto the next game. It looked like my last game so I made the same book
move.

The was a slight difference and my move just lost. I just resigned.

Blunderdog,
Did it have to with being mixed up about which side you were playing? Maybe it had to do with playing both sides in multiple games. Hopefully, it won't be a deciding blunder.

I did get the sides mixed up.