I think one of the challenges (at least for me) is finding the "balance" I had in the states. What I mean by that is I had friends and buddies ages 30 to 55 or so. So we would go do various activities or get togethers whether a sports game, camping, motorcycle riding, boating, weekends to Vegas, motors sports events or just big house parties etc. The discussions topics were all over the place which made it refreshing and fun.
Here the vast majority of foreigners are old, many have ailments which limits their capabilities to do things, many are whiners and complain leading to discussions that are extremely boring. Others I have met in various business venues have typically been drunken loud mouths after a few beers. When it comes to younger Thai people I associate with at work, they have very very limited interests and honestly do not have disposable income to go off and do different things that I grew up doing and still like to do. So establishing that "Balance", if you will, is extremely difficult. Plus if you toss in that many people you meet here are from other countries you find quickly you have absolutely zero in common with them and you just can't relate to what they did in their home country.
I frequently tell other expats that say they want to move abroad for a job like I am doing. It is a key point one should consider, especially if you are social, hobby driven, active type. At this time I find I do most of my stuff alone and do enjoy it. You make it what it is. My wife is very supportive and has enjoyed trying some and now likes many.