I always appreciate a thank you text, as long as it doesn't devolve into "So do you fancy a drink when you're finished tomorrow?" - had a that a few times! But most are just genuinely saying thanks, which is lovely.
When a client shows he appreciates that you're running a business, e.g. if he's running late he'll say "Is it okay still to have an hour at quarter past or do you have another booking?"
Clients who elicit consent for everything are always appreciated - e.g. during OWO if they say "Is it okay if I hold your hair?" rather than just trying to grab on and face fuck. Or "Can I slap your arse?" during doggy.
Definitely agree with clients who have medical problems telling you up front. Makes the booking so much better and I find these very rewarding.
When a client has the right money ready it's always a bonus, although it annoys me if it's in an envelope. I still have to get it out and count it.
A tip is of course always lovely. I have found quite often that if a client gives me more than my fee, if I say "Oh, there's 140 here but I'm only charging 120 today, here's 20 back" they will often tell me to keep it. Likewise if I'm charging an odd tenner, I'll say "Oh I have a tenner somewhere, just a sec" and they'll often say "Oh keep the change." I sometimes get the impression that if I didn't offer, they would insist on the change, and I can totally understand that viewpoint. If I rocked up at my hairdressers and gave them ?80 for a ?70 cut and colour and they just didn't offer me change I'd be really fucked off.
This is a really great thread. It's always good to remind ourselves that there are lovely customers out there when it feels like you've been beset by arseholes!