Your own emotions play a large part in the way a pill, any pill, will affect you. If you're in a good mood, feeling energised and ready to party, you're more likely to feel like dancing. If you're feeling relaxed, still ready for a good night, but not really amped up, then you're more likely to sit and chat.
And even if you feel exactly the same before going out on the two occasions, there are many other things that can happen to you throughout the night that will change your mood.
I find that I can do either on a pill, that is either dance my butt off or sit and chat. It really depends on the atmosphere, on the people around me and the music... For me the pill no longer makes me dance or just sit on my ass. The strength of the pill can affect my willingness to get up and dance (white mitsi = sitting on my ass all night soaking up the euphoria
)
A while back I had a batch of gold cK's (mmmm). Took one one night, danced for about 2 hrs, then spent the rest of the night on my butt (think it was at Teriyaki). Then at Kryal Castle I had another, didn't dance all that much, just went off and chatted for ages, then sat near the fire cos I was freezing. Can't remember the next couple of times, but I'd say they would have been different too...
Experience, tolerance, environment, and simply the different ways the drug affects different people all have a part in determining how you'll feel and what you'll feel like doing.
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Accept that some days you are the pigeon and some days the statue.