A smile, good manners, and a respectful demeanor will go a long way towards changing that perception. If you like, pack a roll of your favorite TP in your suitcase. And always remember to take along a small packet of either tissue or toilet paper whenever you go out. If you also pack your antibacterial hand wipes or liquid hand cleaner for use afterwards, you will be well prepared. Be aware that the use of toilet paper designed for Western-style flush toilets can be a menace in other toilet facilities, especially in those countries where water is precious.
Foreign toilets are sometimes low powered or low tech and can easily clog.
Wash your hands thoroughly throughout the day but especially before eating and after going to the bathroom. Keep nails short, and keep your hands away from your face at all times.