I want to start off by saying bitcoin has never been hacked, many in the media make it look like bitcoin is hackable and not safe, but the truth is people are hackable and clients they use 3rd party are not safe, not bitcoin itself.

Some of the "hacks" I have encountered over the years, hopefully this helps you be a safer user. Please feel free to add more, or possibly think into the future way`s people may do to help secure bitcoin users.

1. The first thing and most common is people using a skeleton key, A skeleton key is when you use the same password for everything, If you check this site https://haveibeenpwned.com/ many big websites you have used leaked your passwords and emails (LinkedIn, This forum, Myspace, are just to name a few). If you have coins on a exchange and you use the same password as your email, consider your coins gone. In addition If you are using coins on a exchange you did not read the first sentence of the white paper and I suggest you do that before holding any bitcoins, it is meant to be p2p and not go through two financial institution.

2. Similar and common to the one above, if you are using a weak password, people can use a program(brute force as example) to figure out your email password in seconds. Make sure you password is not something small, the more numbers and the more letters and combinations of them, the more time you buy yourself. The best is if you mix your passwords up daily or make a bot that auto scrambles your passwords to a new one every few hours so you don`t have to do it manually.

3. Keyloggers, similar and common to the one above, if you are using a public computer, or maybe have malware on your own, they may be able to log all of your passwords and if they have a connection through something like remote viewing to your computer, they can steal all of your coins. Stay away from public computers when using bitcoin and regularly check your computer for viruses, just like us human`s sometimes they need a good cleaning.

4. Malware hack, This is a copy and paste hack where when you try to post your address when sending bitcoin and it get`s replaced by the hackers, Always double check to make sure the address you are sending to is the one you copy and pasted. If it is not, you probably have Malware on your computer.

5. Trusting 3rd party software, I used to play on a anti cheat client called ESEA, for counter-strike (a video game). When I would go to sleep my computer was used to mine bitcoin, in a zombie network so I would not notice.
https://www.theregister.co.uk/2013/11/20/esea_gaming_bitcoin_fine/
Trusting, things like steam client, discord app, blizzard client, (any game, client or program) On the computer you have your wallet can put you at risk. These companies can change their terms and services at any time. They also may be exposed to 3rd party hackers taking advantage of the weaknesses in their clients. Try not to have any additional app`s on your computer other than the necessary ones to run your OS.

6. A lot of people think 2FA is 100% safe, It is not.  Hackers can call up your phone companies and steal your sim card and number, some can spoof your own number. Do not have faith in 2FA on exchanges, it has been proven it is not safe 100`s of times now. I believe the best way to store bitcoins may be a hotwallet with a password mixer on your own computer not attached to the internet, but I think cold wallets may be good to. Sure some 2FA`s help, but it is not 100% secure. You probably want to use Linux to, not windows or apple shit or whatever horrid OS your phone is running on.

Just remember, if you do not hold your banana guys, you are trusting another man holding onto your banana, This defeats the purpose of bitcoin.

There is a few more things like ransomware, social engineering, scams(bitcoin doublers), phishing links(sites that look like the real one but are not) and many tricks people use on social media, so be careful.  

Perhaps some more experience members can give their two satoshi`s on the subject and experiences to help new users out (get it instead of 2 cents, ok I know it was lame). I would also love to hear some theory's how people may steal coins in the future or ones I did not list, I think I got some ideas on what will happen.