Not even Dell will necessarily grow like Dell forever. From April 23rd of this year through November 4th, the stock has lost nearly a third of its value. If that can happen at a company as good as Abbott, it can happen anywhere. You can't expect your company's stock to go up indefinitely just because you want it to. There are 80 million other American investors who don't give a flip whether you own Bell Atlantic stock or not, and they're not going to keep sending the stock up to the moon as a personal favor to you.
Every stock does.
And when it does, you'll be glad you don't have the lion's share of your retirement kitty in it. In farm country, where I grew up, we used to say it's better to be a horse than a cow, because a horse doesn't sleep in the same place it goes to the bathroom. That's even more true for stock than it is for livestock. You don't want too much of your financial capital tied up in the same place. Sleeping in the same place you go to the bathroom is as bad for your diversification as it is for your hygiene.