I agree with what Phil said. I'd like to add that another undersirable part of boredom is if you are stuck doing a boring activity, then it's extremely annoying because you think about all the other interesting things you could be doing during that time instead. e.g. if you are waiting for a bus to arrive which is running late, or if you are stuck talking to someone boring, you are thinking about other fun things you could be doing in that time instead (including doing nothing - but in a more comfortable setting, like at home). The other part of boredom is that time seems to pass very slowly, so it makes it seem even more boring.