Bitcoin first crypto currency and with high market value, all other is alt, so I think they will never reach that point.

how are monero and blackcoin the same or different?  those two confuse me

I agree, bitcoin or bust.  However, I have an irrational love affair with DOGE.  I like the no need for decimal place trait and the extremely quick confirmation times.  I don't like the price volatility and dearth of merchants who accept it.  Bitcoin is volatile as well, but I did buy some silver coins with it.

Though I am not new to btc world and clearly understand the difference between btc/ltc/doge, I still new to trading world, so why'd people dislike doge so much? I know its rate is low, but . . .  does it not profitable or something?

So, in your opinion, is it not worth investing? As for now, I collect doge merely from faucets and use them to learn how to trade, should I stop collecting it from faucet, then?

I don't think this crypto currencies are the same, Bitcoin is the first and the most famous crypto currency online till now, the doge coin , lite coin are just altcoins trying to duplicate the Bitcoin's success but still far from the Bitcoin usability

I don't know much about dogecoin and litecoin but although them seen all same, it have a little difference feature with bitcoin

They are all cryptocurrencies.
Biggest difference: Bitcoin is father of all and have biggest market. It created millionaires.
Litecoin is soft alternative to bitcoin, but it may be counted as only successful alternative.
Other one is just internet meme named coin. It is more like fun thing.

As for now, I try to learn on how to trade using doge and lite which i got from faucets, I completely understand that since I collect them from faucet, there's nothing to lose except my time, but what pick my curiosity is how worthy it is to collect doge faucet? I mean, we all know the difficulties and annoyance on collecting coin from faucet, some people even consider that faucet-collecting is such a waste of time. So... if doge is a waste of time and faucet is a waste of time, that make doge-collecting-faucet a . . . . what? The waste of a waste of time?