Did the red carpet for the Brits yesterday and went to an event on Monday so have a few to add, all nice thankfully! (probably gonna forget loads!)
Vicky Pattison - Really lovely and down to earth, exactly as she was in the jungle, took multiple photos in different poses so I could choose the best one

(I use all 4)
Dan and Phil - Nice enough
Rickie Haywood
Lawson
Louis Tomlinson - This surprised me the most, in the press he'd came off pretty badly, so was expecting similar, but such a nice guy, spent about 20 minutes taking pictures with everybody compared to most peoples 2 or 3 minutes.
Reggie Yates - Lovely as usual
Olly Murs - really genuine
Nick Grimshaw - Really nice, made a lot of effort to speak to everyone
Alesha Dixon - A lot prettier in person
Caroline Flack - Really awesome, as a fan of hers on Strictly I was really pleased she was that nice

George Shelley - See tzsujme post above, agree with all of it.
Years and Years - met Olly before, but the other two are amazing
Lucky Blue Smith (yes thats a name)
Kimberly Wyatt
Ashley Roberts - really sweet, when she took my phone to have a picture, she took
this as well, really cracked me up when I looked back on my photos last night!
Jim Chapman - Means absolutely nothing to 90% of DS posters haha
Jamie Redknapp
Louise Redknapp - at this point I was exhausted, I'd left my phone on the 'photos' app, once I'd taken it off of that I'd put in the wrong camera mode as well, really lovely about it, the guy in front had dropped something on the red carpet so she picked that up for him as well, we overworked the poor woman haha
Emma Bunton - I've been a Spice Girls fan since a young age (she was my first crush, that worked out well didn't it

) and Emma was always my favourite, so glad to see that she is nice and genuine, even got a joint picture with her and Jade.
Jade Jones
Ant and Dec - have been a lifelong fan (ever since the age of 5), so was a great experience
Rihanna - Was standing right near me for 20 minutes without me even noticing it was her

I'd been queuing from 6am in the morning, she was at the o2 entrance about 9am drinking a Costa and I was near the ticket collection area, only noticed it was her when a photo was uploaded onto Twitter, she did the red carpet later on and was lovely
Adele - Just as you see on the telly.
Conor Maynard - Again as a fan for a good 4 years was relieving to know he was nice.
Caspar Lee - Means nothing to 90% of DS.
Craig David - very funny
Labrinth
Cheryl - I've been guilty in the past of not being a fan of her, now I know that she is in fact really nice (Well last night anyway

)
Lana Del Rey
Charli XCX
Sinitta - Very quirky
Judge Rinder
Susanna Reid - Such a pretty woman
Definitely forgot some