I am in private industry now. Too boring

Very relaxed, no pressure at all...but feel that working here is waste of time......and life...
After experiencing the private acctng, I become to be more sure about what I want. ...I think. Just not sure working at midsized cpa firm as manager or working as a senior in big 4(hard for me to directly get manager position in big 4 based on my current package) , which one is better for my final goal...