Answer the question about text:

I could n't believe it because I did n't think I made mistakes like that . Fuuuuuck . He also revamped the long winded version before I could tell him it was the wrong one . No matter , I guess all my prospective employers will get to see every bit of work I have done since like ' 98 .

What may be the reason for them making those mistakes ?
They did n't double check things .