Examples:

• He is such an armchair critic; he has no experience in the subject but he is ready to give plenty of advice.
• He's always criticizing other people's work, but he's never done anything himself, he's just an armchair critic.
• She's always giving her opinions on how things should be done, but she never actually does anything, she's just an armchair critic.
• He's always talking about how he could do things better, but he's never actually done anything, he's just an armchair critic.
• She's always giving her unsolicited opinions, but she's never actually done anything herself, she's just an armchair critic.
• He's always finding fault in others work, but he's never actually done anything himself, he's just an armchair critic.
• She's always giving her thoughts on how things should be done, but she's never actually done it, she's just an armchair critic.
• He's always giving his opinion on things he knows nothing about, he's just an armchair critic.
• She's always giving her critiques, but she's never actually done anything herself, she's just an armchair critic.
• He's always talking about how things should be done, but he's never actually done it himself, he's just an armchair critic.
• She's always giving her thoughts on how things should be done, but she's never actually done it herself, she's just an armchair critic.
• He's always pointing out others mistakes, but he's never actually done anything himself, he's just an armchair critic.
• She's always giving her opinions, but she's never actually done anything herself, she's just an armchair critic.
• He's always talking about how he could do things better, but he's never actually done anything, he's just an armchair critic.
• She's always pointing out others' mistakes, but she's never actually done anything herself, she's just an armchair critic.
• He's always giving his thoughts on how things should be done, but he's never actually done it, he's just an armchair critic.
• She's always giving her critiques, but she's never actually done anything herself, she's just an armchair critic.
• He's always talking about how he could do things better, but he's never actually done anything, he's just an armchair critic.
• She's always pointing out others' mistakes, but she's never actually done anything herself, she's just an armchair critic.
• He's always giving his opinions on things he knows nothing about, he's just an armchair critic.
• She's always giving her thoughts on how things should be done, but she's never actually done it