BE76 PLT BLUNDERED INTO MSP CLASS B AIRSPACE WITHOUT CLRNC.

Narrative

I LEFT M66 AT XA00 FOR A FLT THAT WOULD TAKE ME FIRST TO LVN TO PICK UP A FRIEND AND THEN ON TO MOS. SINCE THE FIRST LEG WOULD BE LARGELY UNDER MSP CLASS B AIRSPACE; I HAD METICULOUSLY PLANNED OUT THAT PART OF THE TRIP (HDGS; ALT; LANDMARKS; ETC). THE FLT TO LVN WENT WITHOUT INCIDENT. THE NEXT LEG TO MOS WOULD BE VFR IN CLASS E AIRSPACE WITH A LNDG AT MOS CLASS G. SINCE ALMOST ALL OF MY FLYING IS OUT OF UNCTLED ARPTS; I HAVE A HABIT OF CLBING DIRECTLY TO CRUISE ALT WHEN VFR; AND SINCE LVN IS NEAR THE OUTER RING OF MSP CLASS B; MY MIND SIMPLY ASSUMED I WOULD BE CLR OF CLASS B BEFORE I CLBED THROUGH 4000 FT MSL. MY BETTER JUDGEMENT NEVER QUESTIONED IT. I NOW REALIZE IT IS POSSIBLE I COULD HAVE UNINTENTIONALLY CLBED THROUGH 4000 FT WHILE STILL 2-3 MI INSIDE MSP CLASS B AIRSPACE. I PRIDE MYSELF IN BEING SAFE AND PROFESSIONAL IN MY FLYING AND NEVER REALIZED HOW ONE SIMPLE LAPSE IN JUDGEMENT COULD CAUSE A POSSIBLE AIRSPACE VIOLATION OR WORSE. WHILE I WILL BE MUCH MORE CAREFUL IN THE FUTURE; PERHAPS A SIGN AT THE END OF THE TXWY WARNING PLTS THEY ARE UNDERLYING CLASS B AIRSPACE WOULD PREVENT THIS TYPE OF INCIDENT.