When considering the risks of "recreational" chemicals, it helps if we distinguish between moreish and addictive. By moreish I mean the tendency to lead to compulsive redosing, and of course when I say addictive I mean in the medium to long term. These can be surprisingly independent. In the case of MDMA, the consensus among drug users, in my experience, is that it's medium high on the moreishness scale but very low on the long term addictiveness scale. In my opinion there is pretty much 0 danger of addiction for the vast majority of less wrongers.

However, from personal experience it can be a very dangerous social lubricant, it lead to multiple social interactions that I later regretted strongly, and this seems to be pretty common.