I mean generally. The biggest thing that pisses me off is I find their pricing really opaque. One near me was advertising 40% off all colour on August, except obviously once you get down to it you realise loads of T&Cs apply.
Pricing systems often totally lack transparency too: you'll be given a rough quote but it's always different at the till because of some bullshit factor like "oh we added a glossing treatment" or "the blow dry was done by a senior stylist".
They often upsell without you realising: at the sink, "oh your ends need a good soak they're very dry. I'm just going to pop on this moisture seal very quickly, is that alright?". Whoops, turns out that was a £20 treatment. It would be great if they were taught to have a bit of honesty in their practices, aka "thus treatment would be great for your hair, it is an extra 20 quid though. Is that okay?".
They chop shit loads off your hair when you go for a trim.
It's 2023 and we're exploring space, but they haven't managed to figure out a sink system that doesn't make you feel like your neck is about to snap. Like thanks for the massaging chair but my head is in agony
So fed up with them!