So many posters have it's displayed when it should be its, don't they.
My own particular bugbear that I hear all the time is when people use the word "I" inappropriately - you wouldn't think our language is that difficult to speak would you? An an example, if I were to say "It took me some time to find the house" why on earth would someone else say "It took John and I a long time to find the house"? I used to correct people (without even thinking really) until someone said "If you correct me again I'll not speak to you any more" lol. So now I keep quiet, but it still upsets me. Sometimes I think the world changed all the rules, and forgot to tell me about it.