When you're a child your parents can seem so foreign and alien. The things they say, the way the dress, how they behave; it can all seem so different to how you imagine you'll live your life. Which is why it's such a shock to slowly (and inevitably) realize you're turning into them. Personally, there are a lot of mom phrases I swore I'd never say that I now say every day and, well, teenage-me would be pissed.
Of course this doesn't happen to everyone, especially if your parents vary wildly from you in terms of beliefs and philosophies or, of course, if they were abusive or toxic. Sometimes parents give their children a concrete blue print of what not to do, and it's easy to become extremely different than your parents. However, for most of us the words and phrases we are surrounded with in our childhoods start to become the soundtrack to our own parenting journey.
For me, its usually in times of stress that I realize I'm essentially channeling my mother. If my son is whining or refusing to get ready in the morning and I don't have the patience or head space to think creatively (or fall back on my education in child development) I'll say some tried and true "mom-isms". I guess the apple doesn't fall too far from the tree.