Time out

My husband and I tend to be a little more lenient  with our grandson then his mother. We don't put him in time out very much. The major offenses are picking on 1 of our 2 Westies or hitting us. When he won't stop either activity he is told he now has to to into the corner for time out. On the way to the corner he gets teary eyed and says, " I am sorry, I am sorry." When he gets in the corner he cries and my shout at us or sit on the floor and move his legs back and forth. If we try and talk with him he shouts,"don't talk to me." The part of this entire process I find most interesting is that he is personally offended we put him in time out and it made him cry.It is not that we are mad at him or he hurt one of the dogs (for whom he shows warm affection for 95% of the time ), or that he is missing out on some other activity. He is 3 years old and stay in time out for 1 to 3 minutes. When the time is up I offer to comfort him . He say no and won't leave the corner. The time outs seem to help. I  now just say that the corner is still there and I don't want to make him cry. He will stop what he is doing.