2018 has been very beneficial for Bitcoin.
What do you mean by very beneficial?
The future of Bitcoin is looking bright so far.
How so? It's been a pretty disappointing year really in my opinion. No huge good news and a whole lot of value being wiped off not only bitcoin but the entire crypto market. The only things I see potentially happening this year or maybe next are the ETFs but I have no idea how much they will benefit the value and whether it'll only be superficial or short-lived or not. Could be huge for bitcoin or a bit of a damp squib.
What are your predictions for the next year i.e 2019? 
Probably the same as this year. A few ups and a few downs. I think the halving in 2020 is the next huge big thing on the bitcoin calendar and hopefully that will start getting priced in to the value during next year.
I could see that you are very supportive for Bitcoins. We are all trying to be optimistic. Thanks for helping!
Everyone should be optimistic though the market has been on the bear market until now. You have to encourage and be optimistic, if you will be like those people who are very skeptic and their pessmistic ideas are coming in you won't grow and you're no longer interested on the future of bitcoin. But we have the same goals here and that is to see the great price of bitcoin.
$30,000 - $50,000 is ideal for 2019.
But I think being blindly optimistic is also setting yourself up for disappointment. What if bitcoin never gets to those highs again. Sure, we all want bitcoin to be worth $20-50k, but that's just wishful thinking. Realistically is that going to happen? Probably not. Call me skeptical or pessimistic if you want but I'd rather be realistic about things than just baselessly speculating on these magic multiple tens of thousands of dollar numbers.