In-Sis-ting.

I have a lot of problems.

They stink (sweater - a person who sweats).

To the retail (re-tail) store.

Marriage.

operate.

opera
rate
per
rat
at
ate
era
ope
op
a

Wheat.

Jack Rabbit.

Because the rolls (roles) weren't good enough.

A hill is hard to get up, a pill is hard to get down.

Stapler.

Polar bears, because their fur is colorless. Each fur strand is actually transparent and pigment free with a hollow core which reflects light.