You really shouldn't be. There is a lot of misconception going around that the 737 is inherently unstable. This is not true. The 737-600/700/800/900 was one of the safest designs ever built (http://www.airsafe.com/events/models/rate_mod.htm). Yet of the few crashes it had, a surprising amount was from pilot disorientation causing them to accidentally stall the plane.

MCAS is not a feature to correct an unstable aircraft, it's to correct a confused pilot. MCAS is triggered if the following circumstances are right: 1) The airspeed is near stalling speed (takeoffs and landings) 2) The AOA (as reported by both sensors now) is greater than the aircraft can climb.

The problem was that 1) the AOA data was faulty, 2) it did not check if there was a disagreement with the backup system 3) The aircraft failed to reset each time it took corrective measures such that each the correction was compounded. 4) the corrective action was 3 times more than approved.

All of these things have been fixed but it also shows how many things have to go wrong for something to be catastrophic. But the max has been built on a solid foundation and that's much better than having to start from scratch.