I think it's not specifically thinking that you should stop doing, but worrying. "Maybe I should just quit and go back to making noodles" is not a phrase he says while thinking, he says it while sulking.

Part of living in the moment, is taking the time to reflect on your feelings and your dreams and judge them against the path that you are on. Just don't cross the line and fall over into the pool, make sure that once you've thought your thoughts you do the things you want and/or need to do to continue on your path.

There is another Oogway quote that can be taken in a similar wrong way. He says "There is just news. There is no good or bad". Immediately after Shifu tells the news and Oogway hilariously responds "that is bad news". He seems to be contradicting himself, but I think the lesson should be taken from his demeanor, not from his literal words. Shifu is clearly distressed about the news, but Oogway takes it calmly. Not worrying, but carefully considering.

Such a great movie :)