One reason I find it hard to like my SIL is because she never got to be a teen/young adult. She had kids early... now that they are older, she is now in the phase where she's out chasing guys, getting drunk, going to clubs. She's almost 40 and one week is banging this guy, the next going after some other guy half her age... trying to get with her son's friends as they turn 18. She cares more about getting drunk with her friends than myself and my DH (her bro) she often forgets plans with us or won't invite us out because she'd rather be whoring it up, or getting into trouble.