Is it difficult to live in Bangkok as a foreigner?

No. Here are some tips to make your life easier in Bangkok as a foreigner

Do not live where other foreigners live.
When foreigners group together they assimilate the culture less.

Eat Thai Food
Do not eat western food every day. You’ve just slowing down your assimilation. Trust me. There is such a variety in all levels of spicing that its just lazy for someone to say “I don’t like Thai food”.

Make Thai Friends
Thai people will make friends with you. Start with people who you buy stuff from every day. Do not frequent the large shopping malls. But from people with small shops. Ask them how business is going. Be friendly!

Go out with Thai People
Invited out by some Thai people? Go! You will be the odd person out, but you will always remember it and people will appreciate that you took the effort even if you cannot understand a word of what is happening.

Learn a few words
A few words like “hello”, “thanks”, “I speak a little thai” can go a long way. It only takes a few minutes. Don’t be lazy.

Read about the culture
Take some time to research on things about the culture that you’re curious about. Have a question? At least look it up on Wikipedia.

Learn the laws
This is not even so required — just do as Thai people do and don’t be stupid or silly.

Respect Thai People
They are just like you. They want the same things as you. Just because they bow or Wei does not mean they are going to go hand over foot for you and give you everything for nothing.

If you care about other people in your general life, you will love Bangkok, or any foreign city. If you’re generally an asshole who thinks only about themself, then you will have problems no matter where you go.