The two worst hotel experiences I had in Thailand were both in Koh Samui. It is a pity because the island is really nice but I think we were unlucky. We arrived to our room which seemed really nice but suddenly we were surrounded by lizards. We requested a second room. When we moved there, there were no lizards but in the morning we even could take a shower. The bathroom was full of ants, mosquitoes, etc. The breakfast, the worst we had in Thailand and the swimming pool was really dirty. Really bad experience. They need to do something to improve quickly.