Well, hot brakes on a -300 after a high speed reject, and a long taxi to the apron resulted in fuse plug melt and damage to brake assembly.
The reversers were not used (don't remember if innoperative at the time ) and the crew did not use the brake cooling schedule from the QRH untill on arriving on the apron,.which proved to be too late.
Sys A hydraulic failure ( hydraulic liquid leaquage ) and also eng oil lost (on different flights ) presented no problems to the crew.
Other than that ,no case of major sys failure that I know of ,in more than 10 yrs of operation with the 737.