I own a few shares of Tesla just because I like the company and I like my Roadster. (For the same reason I own a few shares of Toyota and a few other companies.) But I do not consider it an "investment." It is a sentimental thing. I like feeling that I own a piece of a company I like.
But I would never invest a significant amount of money in any individual stock. And rapid buying/selling to try to capitalize on the short-term fluctuations of the market is nothing but gambling: no different from the roulette wheel or the craps table in Vegas. The stock market reflects a composite of several factors, only one of which is the actual value of a company. Among others are the collective perception of earnings potential, consumer demand, and likelihood of success or collapse of a company. And these factors cannot be anticipated. If you invest for the long term, you don't worry about these fluctuations. Every bit of news will affect a stock's price one way or the other, but unless you are an insider you cannot hope (except by dumb luck, just as in Vegas) to profit from such vagaries.
In my opinion, investing any significant part of your savings in any one company is reckless, and getting excited or angry over short-term changes is pointless.
In my opinion, Tesla is a solid company with excellent chances for long-term success, and an investment in Tesla today will be worth considerable money in twenty years. But, that's just my opinion, and there's also a very real chance that Tesla will fail in the competition with bigger companies when they finally get into the EV market in a big way. And nobody can know what the "real" underlying value of the company is, in order to determine if today's price is high, low, or realistic.
Start-up companies like Tesla are a place to put risk capital: That portion of your savings that you can afford to lose if the price falls or the company goes under. High risk, and high potential for gain.
But it's utterly ridiculous to get angry at Tesla's executives when a news bombshell causes the price to fall 20%, or to get all excited when another news item causes it to rise to a new high.
For me, I like the feeling that I own some of Tesla. I will not lose or make much on it because I don't have a lot in it. I'll keep my shares until some other company offers me a car I like better. My real investments are in mutual funds, where the risk is spread out over lots of issues, both stocks and bonds. Bottom line: Tesla is still a very new company, and as such its price will fluctuate widely with every news item and the vagaries of the markets, and it may give the early investors buckets of money in twenty years, or it may fail when Nissan and BMW and Toyota and others start high-volume production of both luxury and affordable EVs.
