Out of all the lenders, American Express is probably the most risk-averse lender.
Therefore they seem to be the strictest lender when it comes to people who have burned them before or people whom are "riskier" than what they would like.
YMMV in this situation regarding Citi. But i can tell you with certainty, that i personally know of people who have burned Citi, and were later approved. Mind you it was several years later when they applied, but were approved. Later on, one friend was approved for a 2nd Citi card with a very generous credit line. So, i've seen it happen, but of course YMMV, but i'd wait several years before trying again. It's possible perhaps some written off accounts have been purged from bank records for some, and maybe not for others.
When I first turned 18 and went to college, I got sucked into all the credit offers that were thrown at kids during the first week of classes. I remember i got a CITI because I got sucked into the MLM Herbalife. Didn't work out so well. I burned CITI. So my question is, how long do they keep those records on file? Are they along the same lines as AMEX??
According to a friend, they have an endless memory. She burned tham in 1977, and she still cannot get back with them. Good luck to you if you ever app with them again. Stranger things have happened.