In the next few weeks and months, Trump is likely to continue this behavior as pressure mounts and the election comes closer. The closeness of the election is sure to build the stress, and as pressure mounts, he is sure to lose his cool more frequently unless he gives up.
Donald Trump has reached an age where his basic personality and behaviors are going to be impossible to change. He also appears unable to moderate his behavior as he has already gone off script in the things he says publicly. As the rpessure mounts he is only going to get more volatile.
It's the status quo for Donald. However it's also a sign of things to come, since he's wired that way. He's fairly easy to bait and tends to throw tantrums like a toddler. I'd say it's not a quality we want in our next head of state. He's not managed to temper his behavior at all.
Donald Trump losing his cool on Morning Joe is not a sign of things to come. It's a sign of things that are already here. And it is driving the anti-Trump press crazy because the more of these antics he engages in, the more press he gets and the better he does. Stories like this will ensure his election.