Best:
1. BA SIN-SYD. Being op-uped at check-in. Does that count?
2. QF SIN-ADL. Load factor was around 30%. I had a 4-seat Y class "flatbed".
3. CX - SIN-xHKG-SYD return. First time flying CX as a OW sapphire. For the whole set of flights, I was treated like royalty, with crew addressing me by name, and offered special treatments. To this day, I still haven't worked out why, but if they were trying to steal me from QF, they have done a very good job at it.
Worst:
1. QF SYD-NRT. Attempted landing in a storm. It was aborted at minimums, but I was convinced that it would've crashed if it made contact with the tarmac. As far as I know, most international flights simply diverted to KIX, etc, and didn't even bother attempting to (crash) land.
2. BA SYD-SIN. IFE did not work. Reading light stuck on for 3 hours. So there's no entertainment, cannot sleep, and it's 100% packed. Basically, by the end of the flight, I was thankful that the engines were still working all the way into SIN.
3. BA SIN-SYD. Not sure if you would call this good or bad, but the FA was passing out the snack box around. When I got a hold of it, the FA left to do some other tasks, so I had was literally holding the box, and had the full contents to myself and my neighbours. However, we were civilised enough to simply "take one, and pass it on". It went on for quite a few rows before the FA came back to pick up the tab again.
4. JQ SIN-DRW. Red-eye flight. Seats were fixed and did not recline. Enough said.
Honourable & Dishonourable mentions:
SQ SIN-SYD. Nothing wrong with the flight, but having 10+ drinks before boarding is not smart.
QF SIN-MEL. The dragons at the SIN QC managed to give me a spare seat in the block of 2 at the back of the 744, and that was the only spare seat on that flight.
3K SIN-HKG. Being one of the only pax who purchased the plus bundle, I received personal service from the FA, asking what I would like for my meal, and being served first. They came back to offer me drinks afterwards. Neighbouring pax look on with jealousy.
JQ SYD-DRW. Met my ex on that fateful flight.
JQ SYD-DRW. Punctured tyre, resulting in missed connection at DRW. Mislead by SYD ground crew that the DRW-SIN flight will wait. Forced to overnight in DRW, but spent the next day exploring the area, including seeing wild crocs jumping out of the river. Note: this flight was not related to the above mentioned flight.