She has made some really poor decisions.
I fully expected her to create a cross party ‘committee/department, etc’ on Brexit. But to be fair, I am not sure how that would have worked in practice, but it was never suggested or attempted. (Corbyn may have turned down the opportunity, but then it would have placed him at a disadvantage)
She listened to her two stupid advisers, and bought into the myth of her ‘kitten heel’ shoes, spending more time focusing on her shoes at the conservative party conference, than on her speech (the coughing one; according to one newspaper).
Had silly photos of herself wearing fancy leather trousers. (Yes, I know that male leaders also wear expensive suits, but maybe suits are not so obvious)
She stupidly called a ‘snap’ General Election, that was not really ‘snap’ (ie minimum 4 weeks), allowing around 7 weeks, giving time for the Labour Party to get their manifesto out first and set the agenda.
Despite really calling the GE over Brexit, it was fought on domestic issues such as foxhunting, grammar schools and the so-called dementia tax.
Her advisers promoted her, and pushed other bigwigs in the Conservatives to the margins, etc (there is sooo much I could say about the GE).
So she lost her majority, thus relying on the DUP. (This is the key bad decision of hers)
She created David Davies Brexit secretary, but went behind his back to a) agree the EUs timetable of negotiations, and b) agree the WA with Angela Merkel, which she presented as a done deal, at the Chequers meeting, all while DD was negotiating a different agreement.
Refusal to consider other alternatives. (Maybe not possible, but there could have bee, say, a smaller ref in NI only on whether a border across NI or in the Irish Sea is preferable (OK maybe this is a silly idea, but this is just an example).
So, I don't feel sorry for her, and she should probably have resigned when there was a challenge last December.