Are players too moody?

Man City made offers for three of my players. Only them no one else. I tried to renegotiate the offers (reasonable offers too) but they weren't willing to pay.

All three players went in a mood/unhappy. A month later they're still off on one, and one of the players has asked for a transfer.

I haven't unsettled anyone that well. It should not be that easy.

I've had players throw a strop for being warned for skipping training, and for not 'getting enough support' in post-match team talks.

It's a difficult balancing act, and I think it's pretty close to being accurate, though I would say players are a little too sensitive in many cases