Have you ever quit a playthrough?

I've replayed the OT many, many times. I have been trying it as an infiltrator and I just don't vibe with it. I'm in ME3 act 2 and wondering if I should just retire it and go back to a playstyle I enjoy more. The only 2 classes I haven't done for the OT are Infiltrator and Soldier. My preference is adept, vanguard or sent.