what does this sentence mean "you can see where he'd have trouble"in season 1 "Friends"
that's what Ross said to Rachel when Rachel talked with her dad on phone

Rachel: C'mon Daddy, listen to me! It's like, it's like, all of my life, everyone has always told me, 'You're a shoe! You're a shoe, you're a shoe, you're a shoe!'. And today I just stopped and I said, 'What if I don't wanna be a shoe? What if I wanna be a- a purse, y'know? Or a- or a hat! No, I'm not saying I want you to buy me a hat, I'm saying I am a ha- It's a metaphor, Daddy!
Ross: You can see where he'd have trouble.

Question

what does this sentence mean "you can see where he'd have trouble"in season 1 "Friends"
that's what Ross said to Rachel when Rachel talked with her dad on phone

Rachel: C'mon Daddy, listen to me! It's like, it's like, all of my life, everyone has always told me, 'You're a shoe! You're a shoe, you're a shoe, you're a shoe!'. And today I just stopped and I said, 'What if I don't wanna be a shoe? What if I wanna be a- a purse, y'know? Or a- or a hat! No, I'm not saying I want you to buy me a hat, I'm saying I am a ha- It's a metaphor, Daddy!
Ross: You can see where he'd have trouble.

Answer

We say in a sarcastic way:  "You could see where he'd have trouble"  to mean that someone isn't quite smart enough to negociate all situations in life: where one might have trouble is an area they are unfamiliar with.  If you eat in restaurants every day for lunch and dinner, you might have trouble cooking yourself dinner..... If someone knows nothing about anatomy, or science they would have trouble telling you about muscle cell structure.

Answer

you can see where he'd have trouble.＝你现在知道，他为什么有时这么二儿了。

Answer

You can see where he would have trouble  in catching your metaphor.