Here is a list of probable reasons for the unreasonable result of the GE 2015:
1. No contest between house/estate and democracy.
2. Too many "rubbish" parties - RP, NSP, SPP, SFP. SDA. There was just no choice.
3. Credible ones like the WP and SDP have been tainted historically, fairly or unfairly.
4. No one can (be allowed to) run town councils and balance the books except the PAP.
5. Gerrymandering - attending this masterclass is required to qualify for PAP senior membership and win elections.
6. Reverse mote and beam effect.
7. Miracle - Rising from the dead (LKY effect)
8. Feel good factor - SG50, freebies, fireworks, and PGP.
9. Military might - Leopard Tanks on the streets during National Day celebrations
10. Hungry Ghosts have packed up and heading for the door.
Seriously, this is CNA's analysis.