I agree with you. I also prefer watching a movie inside my own home.. or any other home
At home i can pause it, rewind it, i can answer my phone i could go to sleep and see the rest of it the next day.. i can do whatever i want!
The thing with friends is different for me.. i have nothing against spoilers :D
I don't even mind knowing the end of the movie, there is always something more that the friend didn't say.. so i don't mind knowing parts of the movie.