Awkwardness

I was watching this anime called Suzuka yesterday, and two characters who had been going out, broke up. A short summary of it:

Yamato and Honoka have been going out for a little while now, but initially Yamato had only eyes for this girl Suzuka, but after being turned down and snubbed many times, he learned that this girl, Honoka liked him, one thing lead to another and they end up dating. But Yamato is inexperienced with relationships, so he makes many mistakes. Honoka puts up with it pretty well, partly because she really likes Yamato, and also because she is inexperienced as well. The breaking point was when Yamato goes shopping, for Honoka's birthday present, with Suzuka and Honoka finds out about this, but she plays it off as nothing significant. She was ready to accept Yamato's birthday present, but then he starts going on and on about Suzuka, how she helped him, and how annoying she was sometimes. Honoka doesn't want to hear this and gets really mad at Yamato and refuses to accept the present. They eventually agree that breaking up would be the best idea, but Honoka chooses to keep the birthday present, because she still harbors feelings for Yamato. Their first initial meeting after the break-up is right outside their class, and it is extremely awkward.

Is this really the case for relationships? When two people break-up, but still are contact with each other, is it really awkward, and weird afterwards? Sometimes there is hardly a days difference, between the break-up and seeing the person again. One day you are holding hands, laughing together and being a couple, and the next it's like you are meeting a new person. I can understand more weirdness if you were a lot more intimate, but if you had just been kissing, then what makes it so weird to see the person again? I think that the awkwardness is only there because the couple still harbor feelings for one another (or it could be one sided), but even if it is a mutual break-up there can be some tension (which there usually is) between the two people.