overkill13

I haven't tried it yet myself, but this mod purports to reduce the spam to 1 message per day.  There does not appear to be an option to reduce these notifications in the stock game.
 
 

Occasionally I have had the game glitch and apply phantom forces to my ship, often after a maneuver burn.  Changing scenes to the tracking station or space centre and back typically clears up the issue.

Kerbal G-Force limits will cause Kerbals to pass out if they exceed the limit.  The ship, usually a plane, will become uncontrollable until the pilot wakes up, unless a probe core is also present.  The limits also allow the game to generate contracts for Kerbals that want to be in particular situations (flying, sub-orbital or in orbit) and then be subjected to enough G forces to knock them out.  Regular, non-G contracts, will fail if any tourist is rendered unconscious so soften up those reentry procedures and parachute decelerations.
Pressure limits will cause parts to explode if they descend too far in the ocean, at least on Kerbin.  Cannot comment on the pressures found in Eve or Laythe's oceans however or Eve or Jool's atmosphere.
I've never seen a part fail or explode from the G force limits on parts.
I enjoy the Kerbal G limit contracts, the other two I leave off, personally.

EVA and stay close to the command pod.  Right click on command pod and there should be an option to take data.  This should take ALL data on the pod.  Take said data and EVA over to and enter the landing command pod, the Kerbal will drop the data off in the pod on the way through the door.  There is also an option to manually leave the data, but the Kerbal will do it upon entering the pod.