A lot of people encourage over aggressive behavior in their pets without really knowing it. That's where obedience training comes in. I don't think it is for the dogs so much as for the people. Quite often, if you really look at your family, you will discover someone who is encouraging behaviors that you don't want. In one friend's family, they had a dog who jumped up on everyone. The kids and mom were trying to train her not to jump, but as soon as dad came home he pounded on his chest and started to get her to jump on him and wrestle. Duh. I told him he might consider having her sit, give her a treat, then if he wants to wrestle, get down on the floor with her to play. Obedience training worked out MUCH better after he took my advice.
I've also been told that if you have agression problems with a dog, you should avoid the much-loved games of tug-of-war and go for fetch. Luckily with my JRs, aggression wasn't a problem (I understand that is unusual).
Oh, BTW, by the time I had a chance to mention the too-tight collar, they had fixed the problem themselves. Their dog had a growth spurt and they'd not noticed.
Dina, I know this is much-belated, but have you had your dalmation checked for deafness? It is a common problem with dalmations and can make them difficult to train. Many breeds "suffer" from popularity, as has been mentioned before. They get over-bred. Dalmations are one breed that has had that problem since the movies popularized them. You can check your dog for deafness very easily. Sometimes they aren't ignoring your commands, they simply cannot hear you. Sneak up behind with a whistle, a can with pennies in it, or even just clapping your hands. If you can't startle your dog, there you go.
When Keiki got lost, we thought she was gone for good because we knew she was close to totally deaf. Only a miracle brought her back to us. Needless to say, we don't much complain about her "accidents" any more.