I was offered a significant amount of money to switch companies years ago, but preferred to stay with the one I was with as the future with them looked better. Ultimately it was the right decision, as someone else I knew took up the offer and his career went down the pan.
... fair play to you but the analogy doesn't work here ... Spurs future looking brighter than that of Real Madrid?
If Barca or Real seriously came in for Riyad Mahrez he'd more than likely go ... and whilst I'd be really sorry to see him go, as he is, IMHO, the most skillful player I have seen at the club in all my time watching, he'd have my best wishes and gratitude for what he has done for us in his time here ...
... different to your situation perhaps, because Dele Alli hasn't yet contributed to any tangible trophy success for the club ... so it's more unfulfilled promise and a sense of "what might have been" should he leave ...
that's a first.
