Why Linux start suck

I am Linux user and was used it for some time, maybe I must not say such words as the title of this post, but it is enough of me, I should say Linux start suck! So maybe you will ask yourself why? and here is coming my answer.
A few years ago, when I just start to use Linux, I just get in love with it. It was very fast, I liked the design, I liked that is not stuck, yes there was other problems like configuration and installing, but I liked it.
What is happening no? May be this is only for my distribution, Ubuntu or maybe other distribution behave the same, but I start to hate it and this is because my whole system get stuck because of some application. I remember the days ago, when some application start to go slow, it was just that application, now for me, it is going to go slow and even stuck my whole system. For the last few months I should restart my computer by force, almost each 3-5 days. 
So if it will go so, I am afraid that I will move to something else, I even do not want to think about what I will use :(