That's a great attitude to have. Sanchez is a winner. That's what Liverpool, Untied and City don't have enough of - and Arsenal have lacked them over the past decade.
He isn't content with just being a leader, he's a born winner. That's a fantastic attribute in the PL and will stand him in good stead for next season, you'd imagine.
I think he can be aggrieved with the early CL exit, but the PL was unachievable after Mourinho strengthened Chelsea last summer and I guess you can be disappointed with the nature of the defeat to Southampton at the Emirates in the League Cup, but that type of result happens and Southampton were enjoying a resurgence under Koeman at the time.
Forster was great on the night too, if I recall correctly.