unintentional

i got a 'message memory full' message in my phone last night.  to free up space, i checked-out old messages deleting those i could forego.  while reading a certain message, a call came in.  i therefore pressed what i thought was the key that would take the call.  guess what, it rang instead the sender of the message i was reviewing.  oh, no!  aaaarrrrgghh!!!