I joined a big high tech company after I graduated from college. The company was a industry leader (and still is). The company was doing very well and stock kept going up. I loved my company so much and kept buying its stock with ESPP. I told my friends how great this company is and convinced them and myself that investing this company is safe.... Guess what, I still own this company stock but its price is lower than what I paid for many years ago.
The problem with industry leader is everyone knows it's the leader, therefore, the stock is most likely already priced in. Everyone expects it keeps going up, like 芝麻开花节节高. It is not allowed to make ANY mistake. However, let's face it, no company can be "growth" forever. They'll become "value" or "no value" sooner or later.
Conclusion: don't love the company; love your family. Trade the sucker!!! LOL
Just my 2 cents.