I think that the more import first question for anyone coming to Thailand to retire is to decide what they actually want to do in retirement.
In my opinion, going from having the large majority of your waking life organised by 'Work' to having all your waking time 'available' is a huge change in most people's life.
It is vital that you decide how you would like to fill that time.
For some it is sports (especially golf), for some it is to further your education (either by learning a new language, or just about anything via the Internet), for some it is a new 'mini career' (like building something... a building, a wall, a pond, anything) & some just 'do nothing'.
What you decide to do very much depends on your character & what you have already done in life. It is also necessary to consider that while having a great deal of free time on your hands might appeal greatly in the short term after years of being at others beck & call, it might pale after a while. It is better not to burn all bridges immediately on retirement, as you might be wanting to re-cross some of them after six months or so. It is equally important that you give it a real go though & don't think that the location is the issue when it is actually really other things.
Having decided what you are going to spend a great deal of your new found freedom actually doing, then the 'in which location' probably takes care of itself.
As others have indicated, having decided where is for you it is really important that you spend a fair amount of time 'testing the water' before jumping in to discover that, for example, sleep after 6 am in the morning is impossible, or before 2am in the morning - because of neighbourhood factors that are not immediately apparent.
I think, with the right attitude & outlook, either living experience can be either a pleasant, or unpleasant one. That depends far more on the person (& couple

) than the actual environment & can, certainly, can change as retirement progresses..