In my specific situation, I found that 'residual anger', just anger at everything, resentment, stress, a generalized fear that I should be/know better and such on my part colored all the conversations negatively for me. It went up to the point where it enters jokes of "what (s)he says, what (s)he hears" proportions. As an example, an offer to help me with some chore like cooking or painting a wall meant that I heard 'you can't do it, so I'll do it for you'. So I guess the first thing to do is to realize that it's you who's turning everything upside down, and that it means you've got to work on yourself to get it the right way up again.
One way to deal with your dad is to realize that it may just be an excuse to talk to you and hear news about you. My father calls me about 2 times a year, 4 at most. He feels emberrassed calling 'just to talk'. After getting over the ritual start (found a job yet? no? well, how are you doing besides?) you can just talk. If he's really just calling to hear about a job and calls regularly for other stuff too, tell him 'don't call me, I'll call you' on job related stuff.
To continue on that, a change of perspective:
a) is oversimplifying
The person you're talking to, far from considering you stupid, is uncertain about his or her own ability to explain. They assume that they're so bad at explaining that if they don't oversimplify, repeat and such, people can't understand them, because they're just so bad at expressing themself
edit:
I used to suffer from this a lot, both recieving and doing it. I still do sometimes, but not as much. If I explain too much, it's not that I think you're stupid, I think I'm no good at explaining, so I overcompensate. If someone does the same with me, I get angry because they seem to think I'm stupid. Egocentrism at work in its natural environment...
b) not serious
Option 1: It's been tiring and distracting lately for him/her. Concentration is far off, a break, holiday or just sleep would be nice. A tendency to make stupid jokes comes along.
Option 2: (s)he is uncertain among current company and reverts back to old behavior that (s)he (subconciously) knows will break the ice, create laughter and raise peoples esteem of him/her. Behavior from teenage years follows with immature jokes and behavior. When (s)he notices it's not working, fear of being rejected only makes him/her redouble his/her efforts.
I'm sure you get the tendency. The summary is, to put it harshly, that you're being egocentric. What people do revolves around you. To be fair, most people think like that. An example from my own experience is that If I reacted angry to a seemingly innocent remark, I usually was just tired, or stressed out from other things. If someone else did it, it's because they don't like me or are over-sensitive. I explain their behavior in a relation to me, because it's all about me.
I've only been working on toning down on my own self-importance for a number of months, and it works. I can actually listen to good advice without getting angry for a huge number of reasons (it's my life, don't meddle, as if you know, I've tried that already do you think I'm stupid etc) and just accept that that person cares about me enough to want to see me doing well. I've also gone to work on some anger issues, which surprised a number of people, I'd just gotten that good at hiding it, but it was influencing everything I did.
Good luck