Narendra Parihar recently wrote a blog "Test Automation failures". I copy his first paragraph for your reference and grow your interests to read his blog:
1- How many tester's are really tester, may be 50%, rest 50% were circumferenced into testing world. (Dont beat me for that:-))
A good tester generally does not like coding, he/she likes to be always in test execution phase, hitting severity one bugs all the time..... bottom line, A good tester generally does not like creating scripts. So how do we motivate such folks to start writting automation scripts/code, well show them value of automation to find bugs, that may just fly with them.
3- Biggest tempation for a tester working on test automation is technology and coding. With little code understanding automation tester's make mistake of targeting low hanging fruits. So it works for a release and then die's or involves so much manual effort before running it, that there is absolutely no ROI.
Automate for ROI, without productivity gains automation is waste. Future of Automation is in ROI to start with, next level is to find bugs with automation. Keep that in mind from very begining, low hanging fruits are not always a good choice to run after especially when it comes to automation.