Gear Light with (!) ??

Every now and than, mainly on longer drives (for me) of 20 consecutive miles or more a gear light with a "!" in the middle of it lights up on my dash right next to where is displays what gear I am in like "D" for drive. Anyway I read my manual and I do as it says (turn car off and than on again) and it works and goes away evertime. But my question is, why does it even come on in the first place? The car drives no differently before or after the light comes on, whats the deal?

you need to have the DME & EGS fault codes scanned. that warning lamp indicates the Transmission control unit is seeing a problem somewhere, maybe a DME input.