I'm I just being unfriendly to Mother in Law

Mother in Law arrives tonight for a weekend visit. She hasn't phoned or spoken to me about the visit at all. She doesn't reply to e-mails or phone calls. It bugs me as i think it's polite to speak to the person you're visiting. I did invite her, by note card ( her preffered communication method), so i feel as though I'm accomodating her as well as I can. She doesn't stay at out house as there's not much room. ANYWAY - every time she comes (or we visit her) I get pissed off, angry and irritable. I just find her hard to deal with she likes to visit the kids but so obviously wants nothing from me to the point that often she's rude - I'm usually friendly, tolerant and happy to be with all sorts of folk. I can't understand why I'm so wound up by her. Any thoughts??