I think the only time I have felt inclined to make an official complaint regarding cabin crew (in about 40 years as a frequent SLF) was when the lady seated next to me had a bad migraine and used the very handy water proof bag so I buzzed a CC to dispose of it. The git told me I could leave it under the seat (for 12 hours!

) or dispose of it in the toilet. I felt like pouring it into his pocket.