here are nine disliked elements of wudu':
1. Performing wudu' in an unclean place.
2. Using an excessive amount of water when washing the limbs.
3. Superfluous speech when making wudu'. This includes all speech other than mentioning Allah Almighty and calling on Him. It is related that the Prophet, may Allah bless him and grant him peace, used to say when performing wudu, "Allahumma-ghfir li dhanbi wa wassi' li fi dari wa barik li fi rizqi wa qannini bima razaqtani wa la taftini bima zawayta 'anni (O Allah, forgive me my wrong actions, and expand for me in my house and bless me in my provision. Make me content with what You have provided for me and do not try me by what You have kept away from me)."
4. Washing more than three times and wiping more than once.
5. Beginning with the bottom of the limbs.
6. Exposing the private parts during wudu'. This applies when one is alone or with one's spouse. Otherwise it is haram to expose them.
7. Wiping the neck.
8. Going a long way beyond what is obligatory when washing or wiping the limbs. For example it is disliked to wash a lot of the upper arm when washing the forearms or to wash your shins when washing your feet and so forth.
9. Omitting one of the sunna elements of wudu' deliberately. The prayer is not invalidated by its omission, but it is sunna for the one who omits it to perform that omitted element for future prayers, whether it was omitted deliberately or inadvertently. Any prayer prayed with that wudu' is not repeated, regardless of whether the omission was deliberate or inadvertent, and regardless of whether the time of that prayer still remains or has ended. The sunna elements which are made up if they are omitted are three: rinsing the mouth, sniffing water up the nose and wiping the ears. The other sunna elements are not made up; these are: washing the hands, bringing the hands back when wiping the head, renewing the water for the ears and blowing water out of the nose.