WANT to undermine someone’s self-worth, while still sounding like a nice person? Try these phrases:
‘It’s very jazzy’
See also: ‘colourful’, ‘with-it’ or even ‘fun’ when used with the right tone. You haven’t explicitly said you hate their outfit and they look like a clown, but that is what they’ll realise you meant when they think about it later in the day. Then they’ll start crying.
‘Wow, did you cut it yourself?”
What’s the issue? This is clearly complimenting both their great new hairstyle and the impressive haircutting abilities you’ve assumed they possess. No other possible interpretation. Definitely not that they look like Donald Trump having a worse hair day than usual.
‘I wish I could be that carefree’
If they were carefree, they definitely aren’t anymore. Whatever they have done, it has clearly crossed some sort of line, but they don’t know how or why, and you aren’t going to specify. A genius comment which will keep them awake at night worrying.
‘It’s so cute and cosy!’
This one is specifically about their new house. They know it’s tiny, you know it’s tiny, and they know you are judging the tininess negatively, and yet what you’ve said sounds friendly and warm. ‘Thank you!’ they simper, while seething with hatred inside.
‘It just screams ‘you’’
A good one to use while shopping, when they pick up an ugly dress or pair of shoes for a joke. And it’s an efficient double-whammy, as they’ll be incredibly offended and also start to develop a crippling identity crisis.
‘How are you still single?’
On the surface it sounds like you can’t believe someone as wonderful and attractive as them hasn’t found a partner yet. But on closer examination it suggests there is something fundamentally wrong with them. Put lots of emphasis on the ‘still’ so they’re forced to think about how long they’ve been sad and alone.