Things have changed very fast during the modern age. Every service is easily available on customers door step without any delay or even compromising on quality. These rules are applicable on every industry either they are selling products and services reason behind no one patient enough to stand in a queue for having food, getting the banking services or any kind of product and service. Same rule applies on the website there are plenty of competitors in the market who are providing the faster and better websites with user interactivity.It has huge impact in user experience and while making the the website the primary goal and objective should be to make customer experience good.
Google is also emphasizing on the site load time and it is bringing the huge effect on the site rankings and its Search Engine Optimization. The sites which are loading faster than the others has more edge from comparatively slower loading sites.
By avoiding all the above mentioned problems you can easily make your site faster no matter how good your website looks like with the heavier images or theme in the end it if it is increasing the load time it would be of no use. So select better optimized images and them and by deleting the useless plugins and using only the well optimized plugins you can achieve your goal of making your site faster and better user experience easily.
Things that makes your site slower are unoptimized images, heavy theme, multiple and useless plugins, plenty of ads, huge code and external embedded media. There are multiple online tools like Webpage Test, Page speed Insights, Google Analytics Plugin By Yoast, Yslow, Pingdom Website Speed Test, GTMetrix, P3 (Performance Plugin Profiler), Webpage Analyzer, Load Impact, Page Speed Tool (Internet Marketing Ninjas).