Since Safari is a full browser, and stores cookies, the websites you visit most often may act sluggish. Clearing the History, Cookies and Data, will help to speed things back up. This process is shown using iPhone with iOS 11.
Some may find it difficult to read e-mail messages due to the small text size. You can choose between 5 different text sizes in Gmail. Changing the text size in Gmail is similar on most Android Phones.