https://i.imgsafe.org/145d4e4910.jpg

1) Centralized exchanges will rip you of
2) They constantly manipulate the prices and the order books with customers funds
3) Whenever there is a lot of trading their server will crash
4) They are constantly being hacked whenever it suits them. Most hacks are inside jobs
5) When they offer leverage and margin trading I can guarantee you that they will rip you off

I guess that most of you have noticed that ripple (XRP) have skyrocketed today. Within the last 24 hours it went from 0.00002btc to 0.00007 btc, that is  350% within 24 hours. That is just insane... Seeing this kind of increase I could not resist and deposited to Poloniex 0.3btc and went short on XRP at a price of 0.00005 btc..What happened is that within less than 30 minutes from my order the price went to 0.000070. Obviously a lot of margin calls have happened (my margin call price was less than 0.000068 I think) and minutes later XRP price fell to 0.000038. All the time the price was skyrocketing, their server was crashed, I could not deposit any more funds to avoid the margin call, I could not trade, I could not login I could not do anything...I was hopeless...

..........

Time has passed and I have finally managed to login to my account. Luckily I was not margin called..I even made a slight profit... I guess Polo decided not to completely fuck up with all of their customers funds this time..I consider my self very lucky this time..I have very bad similar experiences with margin trading in Polo, loosing all my funds from manipulated prices..

I guess what I am trying to say is:

1) You should be really careful when you margin trade in centralized exchanges
2) You should be aware of the risks of centralized exchanges. 
3) If you believe in crypto, you should use only centralized exchanges for very short time and use them as fiat gateways. There is no reason to hold your coins there for a long time. Just trade in quickly and out. Do not expose yourself to unnecessary risks

But you may ask...I want to trade and keep my self safe. How can I do that? The answer is so simple..

WELCOME TO THE BITSHARES DEX! 
https://i.imgsafe.org/1500cc6fca.jpg

Bitshares is so many things and can do so many things that cannot be filled in just one post.. It represents so many different things for different people. A couple of things to note about bitshares and Bitshares DEX

1) The bitshares Decentralized Exchange is a DECENTRALIZED exchange. You hold the private keys of your assets. You hold the keys to your castle. If you get hacked (I don't think that ever happended to anyone) it will be because of a poor password and your poor security measures. Not because someone hacked your favorite centralized exchange..
2) Prices can not be manipulated by a centralized authority
3) Bitassets are pegged to real assets. Bitusd to usd, bitbtc to btc, bitgold to gold 
4) In bitshares if you want to short bitassets (i.e. you believe that the price of usd will fall relatively to the price of bts) you need to provide at least x2-2.5 bts collateral on the blockchain. You can think this as a bank that holds x2 ++ collateral of its customer funds at all times for any bitusd into existence. That is bitshares blockchain will never default on its debt unlikely to banks that hold only a 5% of liquid usd from customer funds. 
5) Bitshares DEX is your trading and saving platform.
6) Bitshares can do what ripple does much faster and has by far a better distribution compared to ripple's initial distribution..(Do some research people...)
7) Thanks to blockpay, now any merchant can accept any kind of bitasset and convert to fiat if need be

So why bitshares is so undervalued? 

Honestly, I have no idea...This is just beyond me.I guess it is because most people like to get screwed by centralized exchanges. Obviously centralized exchanges offer much liquidity (with customer funds) so traders obviously like liquidity. Well liquidity is picking up to bitshares DEX as well and it is up to all of us to increase bitshares DEX liquidity. No need for centralized exchanges anymore... Just try it out an see for yourself..

Concluding I would like to say that bitshares community is still very active after 3 years of existence despite all the ups,downs,dramas..Feel free to join our forum at bitsharestalk.org and ask any questions you may have. You will always find someone to assist you.