Out of curiosity, how important is sexual chemistry or sexual compatibility in a relationship? I've always been of the opinion that sex can always be improved upon so even if it starts out bad, with good communication, it can get better so shouldn't be seen as a deal breaker. It's easy to see how lack of sex can be a deal breaker but how many see bad sex as a deal breaker/relationship killer? Any opinions on the subject?

EDIT: Thanks for the responses! I left the definition of bad sex kind of open because I was curious what others considered bad sex versus what I considered bad sex. I really appreciated the different responses. Also realized how big a part physical attraction plays in a relationship. I also think using the terms sexual chemistry, sexual compatibility, and bad sex together painted a different picture for everyone. Great discussion.