yup..each one is different..BB is my first cockatiel. After reading many posts here,I decided on getting one after Smokey passed away. I've always had two birds,amy grew up with Smokey and was depressed like I was when she passed.
Beebs came from a breeder,who has been in business for nearly 40 years,and breeds all sorts of birdies,so I was confident with were BB was coming from.
With getting ANY bird,let him/her choose YOU,it'll make it so much easier when bonding/training begins. Out of four Normal Gray birds available to go home that day,BB was the only one who was interested in me

The other three either didn't give a hoot,or ran away when I got close to them. BB hopped right on my hand and walked up my arm to sit on my shoulder then twittle/chirp in my ear

He had picked ME and he came home with me that day.
Right from the get-go he was a sweet heart. I didn't even put him in his new house when we got home,I let him sit on my shoulder while I played on the computer. He took to head skritches right away. I talked to him as he twittled away ( the very first thing he learned was the wolf whistle,that took about five days for him to get down pat). He was clipped so he couldn't fly,and he hadn't even molted his baby clothes yet (that took what seemed to be a LONG time lol) So for him to get around,he had to use me as his taxi.
I immediately introduced him to friends,to socialize him. My brother when he came over,my son,my buddies Joe and DJ (who are now "Uncle Joe" and "Uncle DJ").
So Beebers got used to new faces fast! He does his wolfie whistle to Joe and DJ..he doesn't even have to see them,just hear their voices lol.
He learned to whistle the andy Griffith and Addams family theme songs very fast. He says a few words very clearly.."little boy..little boy"..."BB good boy!".."hello" "Beebers"..and a few others. He whistles and mixes up on the theme songs lol. I let him learn to fly,which he does very well. He'll fly to me when I call to him.
He plays a game with me..I let him out of his house then sit on the couch. he'll come running across the floor to me saying "c'mon..c'mon" then as soon as he is ready to step up on my hand,he turns and runs off in the other direction,still saying c'mon c'mon lol and he'll do this for five minutes or so then finally step up on my hand
Cockatiels get frightened easily (at least to me). If he gets scared,he'll take off flying at full throttle,yelling his fool head off,and fly like he is out of control! He has smacked the wall a few times

I was considering getting him clipped at one point,but now he can zoom down the halls and turn on a dime,can even fly in circles in my kitchen without crashing!
I can put my hand around him while he is on my shoulder and kiss his little face and he makes kissy sounds back to me. He will SING HIS HEART OUT,in my ear,beaky pressed to my cheek. As soon as he hears me get up in the morning,doesn't even have to see me,he just lights up and whistles his heart out.
He can/will/does get night frights at times...teils do this..something scares the crap out of him when he is in bed for the night and he thrashes around in his house. I have to get up and turn on the lights and uncover his house and reassure the poor boy
The only thing he really does that bugs the crap outta me is..He WONT stay off my flat screen!

No matter what I do!! I don't want him crapping on it!!! Oh...and he WILL NOT stop and try to do the chaa-chaa on my hand! He is relentless! I shoo him away just for him to walk down my arm to the other hand! Back and forth we go til I get fed up with it and put him back in his house!!!!
did I mention that he'll also "box" with my ear??
I paid $150 for him..If I knew then that he would turn out the way he did,I'd gladly would have paid $1000

This is JMHO though lol.
Jim