Not the biggest fan of Plinko personally; played it already a lot of times, but never hit a high or max multiplier. I don't switch coins nor increase bet size, I always play with the same bet amount. I seem to get more lucky with Limbo or Crash, so I play these games more often than Plinko.
I share your opinion. I never got crazy lucky with Plinko so far even though the house edge is pretty low. However, I have heard stories of people literally becoming rich because of this game right here in Bitcointalk.
For example, a certain gambler turned 100 bucks into 50 grand thanks to a high multiplier win. It all comes down to luck at the end of the day basically.
I also think that the player's personality influences here, a long time ago I really liked games like Poker and Black Jack, in fact I still like them a lot and every time there is a poker tournament I am interested to see if I can participate, but games like Plinko I play very little, because in reality I have not had very good luck there, it seems to me that many things have to happen and especially time to win, in crash it is something more exciting for me, because there is not much risk and You can have good results, however my favorite game is the slots and here in stake many players have had millionaire wins, I think that the slots are where the most winners have been registered.
~snip
Try also to remove your cookie and cache from your browser, maybe can help.
It's working now, thanks for mentioning cookies and cache, I didn't clear it yet first, instead I checked the browser settings and made some tweaks on Privacy and security (Safe Browsing, secure connections, and tracking), so now I can access that site smoothly again.
I am one that you can make you delete that, both the cookies and I wish you could delete history, sometimes in the history there are some Trojan viruses that can prevent access, and can collect your data, you have to be careful especially with the .dat files that they are the ones that hackers are looking for the most.
And I go, and do I make just a "couple" of bets? Never. 
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