2ashamed
I face a similar problem (and I ahve opened another thread on it), in that I didn't want become a parent that shouts as I think it is just as useless as smacking and teaches the child to shout instead of talking, but I still find it difficult sometimes, as you said it's usually when you've had a bad day yourself, you're tired and you lsoe your patience.
I have recently started to make a real effort at being more patient with DD (following also the advice received on mumsnet and a very good book suggested by Aloha).
sO EVERY TIME she is winding me up for some reason, I try all sorts of diversion techniques, then as others have said really whether its actually so important to do what I want to do, then I try and understand WHY she doesn't want to do it, this usually helps me in seeing things the way she sees them, and even though I might insist (if it0s something that really needs doing) I then manage to get on with it without shouting, even through my dd's cries, but she ends up being less upset than she would if I shouted and I don't feel bad about myself, and as a consequence I don't feel resentful toeards DD for putting me in a situation where I behave in a way that I don't like.
I hope this amkes sense, but to amke an example, last night DD didn't want to ahve a bath, but she needed it desperat6ely, I tried gentle persuasion and bathing with mummy, you can wash mummy's hair, let's make bubbles, she still refused. On a bad day I'd start shouting and would put her in the bath kicking and screaming, and the more she fights the m,ore I shout.
Yesterday I told her I know you don't wnat to do this but you really need it, very calm, I put her in the bath and tried to amke it as quickly as possible, and 3 minutes she was clean and I gave her a cuddle and that was it.
I I was a very proud mum (of myself!!!)
I'm not saying it's easy, and I do feel exhausted at the end of the day, as finding ways to avert crisis doesn't come easy to me (very limited imagination), so I ahve to rack my brains really hard, but the more you do it the easier it becomes and it does make life easier....Mind you DD's beahvior has not changed much yet, but her tantrums are shorter because I don't take part in them anymore, and a few are avoided through prevention.
Best of luck and don't be ashamed, we all start with the ebst intentions but we're all human and the fact that we're sorry just proves that we love our children very much!!!!!