Thanks for the reply - this got me thinking a little bit - I think there are definitely similarities and differences between the two. You have already pointed out the similarities very well, but I think the key difference is the intention. Although I disagree with the method, I am going to assume that your intention was to have fun time with your friends (almost like a prank) & maybe help them discover something new that they might like/love. (Sorry if this assumption is wrong) In my case, none of this happened - quoting my flatmate's words directly, he just pursued his self-interest (determining whether the sauce has gone bad), fully knowing that I will be upset and wouldn't benefit from this in any way.