Unsurprisingly, there are many articles published about "The Awful English Language" , such as: [1], [2], [3] Some examples from [2]: Let's face it -- English is a crazy language. Besides the above, there is no egg in eggplant, nor ham in hamburger; neither apple nor pine in pineapple. English muffins weren't invented in England or French fries in France. Sweetmeats are candies while sweetbreads, which aren't sweet,…
All languages have the sort of contradictions that are pointing out there, and English isn't especially bad (in fact, most of the examples there are directly inherited from German). Most of the difficult things in English come from it being a Germanic language with a bunch of French bolted onto it. That's why its spelling is so atrocious and there are a lot of duplicated words with very similar meanings in common use.
But, blessedly, English does have the simplest grammar of probably any European language. (I've occasionally heard that Swedish is the closest in simplicity, also being a Germanic language that's dropped most of the complexity, but isn't quite as inundated with loanwords.) Aside from a couple of concepts (the gerund, specifically, which isn't common in some European language families), most grammatical structures in English have direct equivalents in all other European languages.
However, going the other way is difficult: most European languages have formal and informal voices, gendered nouns, some have irregular plurals (German, notably), subtler and more verb tenses (Romance languages), and complex case structures (German and even worse, Slavic languages). If you're a native English speaker that doesn't know what cases are, for example the word for "the" in German changes based on which of the three genders the noun is and how it's used. It could be "die", "der", "das", "den", "dem" or "des", and the endings of words that need to be in agreement with it change as well.
The main reason English became the modern lingua franca is the British Empire, but it does help that it's also a very easy language.