You can ignore something "annoying" done by another party. You can't ignore a lawsuit. Lawsuits are enforced by a government and legal system that you have no

You can ignore something "annoying" done by another party. You can't ignore a lawsuit. Lawsuits are enforced by a government and legal system that you have no choice but to participate in, and if you lose, the government can send men with guns to take your money and send you to be locked up (or maybe just tell your bank to directly take money from your bank account).