Well, if the volume is not too loud, I usually either choose to watch it, or just simply look away (which is easy for me - I lose sense of what's on after some time of ignoring it). The only times when I find it truely irritating is when:
1. Something's wrong with the screen, yet it's still switched on,
2. When the reception becomes poor,
3. The volume is too loud, and/or
4. Something I hate comes on (damn you Crazy Frog...)
One thing that goes in reverse to TV Mobile though, can be held through. It is when you try to hear what's on, yet the noise of the bus' engine drowns out the volume.
Interestingly, I can relate two of my most memorable TV experinces to TV Mobile, and one of them involved Pokémon if I'm not remembering things wrongly (SBS 1985C, are you reading this?

). It was quite some time ago, and they were doing a movie review for the Pokémon movie "The Power of One", and they happened to show a clip of the movie, and I was staring at a picture of a
Lugia.

So, I would say that TV Mobile is sort of a double-edged sword. On one hand, it provides an alternative entertainment or information outlet when you have nothing much else to do. On the other hand, if any of those four irritating things come on, you have no choice but to bear with it.